179 results on '"A. A. Belik"'
Search Results
2. Crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6
- Author
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Jie Chen, Yoshihiro Tsujimoto, Alexei A. Belik, Kazunari Yamaura, and Yoshitaka Matsushita
- Subjects
crystal structure ,osmate ,oxide ,high-pressure synthesis ,cubic double perovskite ,Crystallography ,QD901-999 - Abstract
The crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6, grown at high pressure, was solved using intensity data measured at 113 K. The Os site was modelled with a partial Ni occupancy, and the Cr site was modelled with both Os and Ni partial occupancy. The refined structure shows that this cubic form is stable at 113 K.
- Published
- 2022
- Full Text
- View/download PDF
3. Investigation of the Crystal Structure and Magnetic Properties of BiMnO3 + δ (δ = 0.08 and 0.14) by the Methods of Neutron Diffraction and Magnetometry.
- Author
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Sikolenko, V. V., Efimov, V. V., Silibin, M. V., Latushko, S. I., Zheludkevich, D. V., Karpinsky, D. V., and Belik, A. A.
- Abstract
The crystal structure of BiMnO
3 + δ ceramic compositions is studied depending on the nominal oxygen content and temperature using neutron diffraction, X-ray diffraction and magnetometry methods. It is found that at room temperature the composition with δ = 0.08 is characterized by a monoclinic structure, while the composition with δ = 0.14 is characterized by a two-phase state with the coexistence of a dominant orthorhombic structure and a monoclinic structure. An increase in temperature leads to a structural phase transition to a nonpolar orthorhombic structure at temperatures of T1 ~ 500 K and T2 ~ 750 K for the compositions δ = 0.08 and δ = 0.14, respectively, while the orthorhombic structure is retained in both compositions up to the temperatures of chemical decomposition. With an increase in the nominal oxygen content from δ = 0.08 to δ = 0.14, the magnetization of the compositions decreases, which is due to destruction of the orbital ordering of Mn3+ ions, while the magnetic state of the compositions changes from ferromagnetic (δ = 0.08) with a temperature of transition to the magnetically ordered state of TC1 ≈ 68 K to the spin-glass-type state (δ = 0.14) with the freezing temperature of magnetic clusters of TC2 ≈ 28 K. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
4. KTb(MoO4)2 Green Phosphor with K+-Ion Conductivity: Derived from Different Synthesis Routes
- Author
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Dmitry A. Spassky, Vladimir A. Morozov, Dina V. Deyneko, Sergey Ya. Istomin, Redkin Boris S, Nikolay V. Lyskov, Aleksandra A. Savina, Bogdan I. Lazoryak, Alexei A. Belik, and Svetlana M. Posokhova
- Subjects
010405 organic chemistry ,Chemistry ,Analytical chemistry ,Crystal structure ,Triclinic crystal system ,010402 general chemistry ,01 natural sciences ,Hydrothermal circulation ,Grain size ,0104 chemical sciences ,Inorganic Chemistry ,Orthorhombic crystal system ,Crystallite ,Physical and Theoretical Chemistry ,Luminescence ,Single crystal - Abstract
The influence of different synthesis routes on the structure and luminescent properties of KTb(MoO4)2 (KTMO) was studied. KTMO samples were prepared by solid-state, hydrothermal, and Czochralski techniques. These methods lead to the following different crystal structures: a triclinic scheelite-type α-phase is the result for the solid-state method, and an orthorhombic KY(MoO4)2-type γ-phase is the result for the hydrothermal and Czochralski techniques. The triclinic α-KTMO phase transforms into the orthorhombic γ-phase when heated at 1273 K above the melting point, while KTMO prepared by the hydrothermal method does not show phase transitions. The influence of treatment conditions on the average crystallite size of orthorhombic KTMO was revealed by X-ray diffraction line broadening measurements. The electrical conductivity was measured on KTMO single crystals. The orthorhombic structure of KTMO that was prepared by the hydrothermal method was refined using synchrotron powder X-ray diffraction data. K+ cations are located in extensive two-dimensional channels along the c-axis and the a-axis. The possibility of K+ migration inside these channels was confirmed by electrical conductivity measurements, where strong anisotropy was observed in different crystallographic directions. The evolution of luminescent properties as a result of synthesis routes and heating and cooling conditions was studied and compared with data for the average crystallite size calculation and the grain size determination. All samples' emission spectra exhibit a strong green emission at 545 nm due to the 5D4 → 7F5 Tb3+ transition. The maximum of the integral intensity emission for the 5D4 → 7F5 emission under λex = 380 nm excitation was found for the KTMO crashed single crystal.
- Published
- 2021
5. Ferrimagnetic and relaxor ferroelectric properties of R2MnMn(MnTi3)O12 perovskites with R = Nd, Eu, and Gd
- Author
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Masahiko Tanaka, Alexei A. Belik, Ran Liu, Hiromu Mori, Yoshiyuki Inaguma, and Kazunari Yamaura
- Subjects
Diffraction ,Materials science ,02 engineering and technology ,General Chemistry ,Dielectric ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Synchrotron ,0104 chemical sciences ,law.invention ,Crystallography ,law ,Ferrimagnetism ,Materials Chemistry ,Polar ,Multiferroics ,0210 nano-technology - Abstract
ABO3 perovskites have a number of ferroelectric instabilities resulting in varieties of long-range and short-range polar distortions. On the other hand, polar distortions are very limited in quadruple perovskites AA′3B4O12 and A2A′A′′B4O12. Here we showed that R2MnMn(MnTi3)O12 oxides, belonging to a family of A-site columnar-ordered quadruple perovskites, exhibit relaxor-like ferroelectric properties slightly below room temperature. They were synthesized by a high-pressure high-temperature method for R = Nd, Eu, and Gd at about 6 GPa and 1570 K. At room temperature they crystallize in centrosymmetric space group P42/nmc (no. 137), and their crystal structures were studied by synchrotron powder X-ray diffraction. They exhibit broad dielectric anomalies just below room temperature with characteristic frequency-dependent features of the relaxor ferroelectric behavior. P–E loop measurements at 77 K confirmed ferroelectricity for R = Nd and Eu. Magnetic and specific heat measurements showed the presence of long-range ferrimagnetic transitions below 20 K (R = Nd), 30 K (R = Eu), and 42 K (R = Gd). Additional specific heat anomalies were observed below about 5 K for R = Nd and Gd probably due to the involvement of rare-earth cations in long-range orderings. The coexistence of ferrimagnetic transitions and relaxor-like ferroelectric properties make R2MnMn(MnTi3)O12 perovskites multiferroic materials.
- Published
- 2021
6. Abnormal Eu 3+ → Eu 2+ Reduction in Ca 9− x Mn x Eu(PO 4) 7 Phosphors: Structure and Luminescent Properties.
- Author
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Sipina, Elena V., Spassky, Dmitry A., Krutyak, Nataliya R., Morozov, Vladimir A., Zhukovskaya, Evgenia S., Belik, Alexei A., Manylov, Mikhail S., Lazoryak, Bogdan I., and Deyneko, Dina V.
- Subjects
ELECTRIC dipole transitions ,PHOSPHORS ,X-ray photoelectron spectroscopy ,TERBIUM ,CRYSTAL structure - Abstract
β-Ca
3 (PO4 )2 -type phosphors Ca9−x Mnx Eu(PO4 )7 have been synthesized by high-temperature solid-phase reactions. The crystal structure of Ca8 MnEu(PO4 )7 was characterized by synchrotron X-ray diffraction. The phase transitions, magnetic and photoluminescence (PL) properties were studied. The abnormal reduction Eu3+ → Eu2+ in air was observed in Ca9−x Mnx Eu(PO4 )7 according to PL spectra study and confirmed by X-ray photoelectron spectroscopy (XPS). Eu3+ shows partial reduction and coexistence of Eu2+ /3+ states. It reflects in combination of a broad band from the Eu2+ 4f6 5d1 → 4f7 transition and a series of sharp lines attributed to5 D0 →7 FJ transitions of Eu3+ . Eu2+ /Eu3+ ions are redistributed among two crystal sites, M1 and M3, while Mn2+ fully occupies octahedral site M5 in Ca8 MnEu(PO4 )7 . The main emission band was attributed to the5 D0 →7 F2 electric dipole transition of Eu3+ at 395 nm excitation. The abnormal quenching of Eu3+ emission was observed in Ca9−x Mnx Eu(PO4 )7 phosphors with doping of the host by Mn2+ ions. The phenomena of abnormal reduction and quenching were discussed in detail. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
7. High-Pressure Synthesis, Crystal Structures, and Properties of A-Site Columnar-Ordered Quadruple Perovskites NaRMn2Ti4O12 with R = Sm, Eu, Gd, Dy, Ho, Y
- Author
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Roger D. Johnson, Rebecca Scatena, Masahiko Tanaka, Kazunari Yamaura, Ran Liu, Yoshiyuki Inaguma, Alexei A. Belik, Dmitry D. Khalyavin, and Yoshitaka Matsushita
- Subjects
Inorganic Chemistry ,A-site ,Crystallography ,Chemistry ,High pressure ,Rare earth ,Crystal structure ,Physical and Theoretical Chemistry - Abstract
The formation of NaRMn2Ti4O12 compounds (R = rare earth) under high pressure (about 6 GPa) and high temperature (about 1750 K) conditions was studied. Such compounds with R = Sm, Eu, Gd, Dy, Ho, Y ...
- Published
- 2020
8. Structural and Magnetic Phase Transitions in BiFe$_{1−x}$Mn$_x$O$_3$ Solid Solution Driven by Temperature
- Author
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Karpinsky, Dmitry V., Silibin, Maxim V., Latushka, Siarhei I., Zhaludkevich, Dmitry V., Sikolenko, Vadim V., Al-Ghamdi, Hanan, Almuqrin, Aljawhara H., Sayyed, M. I., and Belik, Alexei A.
- Subjects
crystal structure ,magnetometry ,Geography & travel ,magnetic state ,multiferroics ,synchrotron diffraction ,ddc:910 ,phase transitions ,X-ray diffraction - Abstract
The crystal structure and magnetic state of the (1 − x)BiFeO$_3$-(x)BiMnO$_3$ solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the room-temperature structural transitions from the polar-active rhombohedral phase to the antipolar orthorhombic phase, and then to the monoclinic phase accompanied by the formation of two-phase regions consisting of the adjacent structural phases in the concentration ranges 0.25 < x$_1$ < 0.30 and 0.50 ≤ x$_2$ < 0.65, respectively. The accompanied changes in the magnetic structure refer to the magnetic transitions from the modulated antiferromagnetic structure to the non-colinear antiferromagnetic structure, and then to the orbitally ordered ferromagnetic structure. The compounds with a two-phase structural state at room temperature are characterized by irreversible temperature-driven structural transitions, which favor the stabilization of high-temperature structural phases. The magnetic structure of the compounds also exhibits an irreversible temperature-induced transition, resulting in an increase of the contribution from the magnetic phase associated with the high-temperature structural phase. The relationship between the structural parameters and the magnetic state of the compounds with a metastable structure is studied and discussed depending on the chemical composition and heating prehistory.
- Published
- 2022
- Full Text
- View/download PDF
9. Crystal and Magnetic Structure Transitions in BiMnO3+δ Ceramics Driven by Cation Vacancies and Temperature
- Author
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Alexei A. Belik, Maxim V. Silibin, Daniel M. Többens, V. V. Sikolenko, Denis Sheptyakov, S.I. Latushka, Dmitry V. Karpinsky, D.V. Zhaludkevich, and V. A. Khomchenko
- Subjects
Phase transition ,Technology ,Materials science ,synchrotron and neutron diffraction ,Geography & travel ,multiferroics ,Crystal structure ,Crystal ,Condensed Matter::Materials Science ,magnetometry ,Antiferromagnetism ,General Materials Science ,crystal and magnetic structure ,orbital ordering ,ddc:910 ,Microscopy ,QC120-168.85 ,Magnetic structure ,QH201-278.5 ,Engineering (General). Civil engineering (General) ,phase transitions ,TK1-9971 ,Crystallography ,Ferromagnetism ,Descriptive and experimental mechanics ,Orthorhombic crystal system ,Condensed Matter::Strongly Correlated Electrons ,Electrical engineering. Electronics. Nuclear engineering ,TA1-2040 ,Monoclinic crystal system - Abstract
The crystal structure of BiMnO3+δ ceramics has been studied as a function of nominal oxygen excess and temperature using synchrotron and neutron powder diffraction, magnetometry and differential scanning calorimetry. Increase in oxygen excess leads to the structural transformations from the monoclinic structure (C2/c) to another monoclinic (P21/c), and then to the orthorhombic (Pnma) structure through the two-phase regions. The sequence of the structural transformations is accompanied by a modification of the orbital ordering followed by its disruption. Modification of the orbital order leads to a rearrangement of the magnetic structure of the compounds from the long-range ferromagnetic to a mixed magnetic state with antiferromagnetic clusters coexistent in a ferromagnetic matrix followed by a frustration of the long-range magnetic order. Temperature increase causes the structural transition to the nonpolar orthorhombic phase regardless of the structural state at room temperature, the orbital order is destroyed in compounds BiMnO3+δ (δ ≤ 0.14) at temperatures above 470 °C.
- Published
- 2021
10. Temperature-Driven Transformation of the Crystal and Magnetic Structures of BiFe0.7Mn0.3O3 Ceramics
- Author
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Dmitry V. Karpinsky, Maxim V. Silibin, Siarhei I. Latushka, Dmitry V. Zhaludkevich, Vadim V. Sikolenko, Roman Svetogorov, M. I. Sayyed, Nouf Almousa, Alex Trukhanov, Sergei Trukhanov, and Alexei А. Belik
- Subjects
General Chemical Engineering ,crystal structure ,magnetic properties ,phase transitions ,synchrotron and neutron diffraction ,functional magnetic oxides ,General Materials Science - Abstract
The compound BiFe0.7Mn0.3O3 consisting at room temperature of coexistent anti-polar orthorhombic and polar rhombohedral phases has a metastable structural state, which has been studied by laboratory X-ray, synchrotron and neutron diffraction, magnetometry, differential thermal analysis, and differential scanning calorimetry. Thermal annealing of the sample at temperatures above the temperature-driven phase transition into the single phase rhombohedral structure (~700 K) causes an increase of the volume fraction of the rhombohedral phase at room temperature from ~10% up to ~30%, which is accompanied by the modification of the magnetic state, leading to strengthening of a ferromagnetic component. A strong external magnetic field (~5 T) applied to the sample notably changes its magnetic properties, as well as provides a reinforcement of the ferromagnetic component, thus leading to an interaction between two magnetic subsystems formed by the antiferromagnetic matrix with non-collinear alignment of magnetic moments and the nanoscale ferromagnetic clusters coexisting within it. The modification of the structural state and magnetic properties of the compounds and a correlation between different structural and magnetic phases are discussed focusing on the effect of thermal annealing and the impact of an external magnetic field.
- Published
- 2022
11. Crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6.
- Author
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Jie Chen, Yoshihiro Tsujimoto, Belik, Alexei A., Kazunari Yamaura, and Yoshitaka Matsushita
- Subjects
- *
CRYSTAL structure , *OSMIUM - Abstract
The crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6, grown at high pressure, was solved using intensity data measured at 113 K. The Os site was modelled with a partial Ni occupancy, and the Cr site was modelled with both Os and Ni partial occupancy. The refined structure shows that this cubic form is stable at 113 K. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6.
- Author
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Jie Chen, Yoshihiro Tsujimoto, Belik, Alexei A., Kazunari Yamaura, and Yoshitaka Matsushita
- Subjects
CRYSTAL structure ,OSMIUM - Abstract
The crystal structure of the cubic double-perovskite Sr2Cr0.84Ni0.09Os1.07O6, grown at high pressure, was solved using intensity data measured at 113 K. The Os site was modelled with a partial Ni occupancy, and the Cr site was modelled with both Os and Ni partial occupancy. The refined structure shows that this cubic form is stable at 113 K. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
13. Spin-Glass Magnetic Properties of A-Site Columnar-Ordered Quadruple Perovskites Y2MnGa(Mn4–xGax)O12 with 0 ≤ x ≤ 3
- Author
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Dmitry D. Khalyavin, Kazunari Yamaura, Fumiyasu Oba, Ran Liu, Yoshio Katsuya, Naoki Tsunoda, Masahiko Tanaka, Yu Kumagai, and Alexei A. Belik
- Subjects
Spin glass ,Chemistry ,Parent structure ,Crystal structure ,Synchrotron ,law.invention ,Inorganic Chemistry ,Crystallography ,Octahedron ,law ,Lattice (order) ,Physical and Theoretical Chemistry ,Perovskite (structure) ,Solid solution - Abstract
Y2MnGa(Mn4–xGax)O12 solid solutions were synthesized at high pressure of ∼6 GPa and high temperature of ∼1570 K for the 0 ≤ x ≤ 3 compositional range. Synchrotron X-ray and neutron powder diffraction were used to study the crystal structures and cation distributions. These solutions adopt the parent structure of the A-site columnar-ordered quadruple perovskite family with space group P42/nmc (No. 137). They have lattice parameters of a = 7.36095 A and c = 7.753 84 A (x = 0), a = 7.361 68 A and c = 7.716 16 A (x = 1), a = 7.360 34 A and c = 7.67142 A (x = 2), and a = 7.363 93 A and c = 7.616 85 A (x = 3) at room temperature. The x = 0 sample has a cation distribution of [Y3+2]A[Mn3+]A′[Ga3+0.68Mn2+0.32]A″[Mn3.68Ga0.32]BO12 with a preferred localization of Ga3+ in the tetrahedral A″ site and with a small amount of Ga3+ in the octahedral B site. A complete triple A-site order, [Y3+2]A[Mn3+]A′[Ga3+]A″[Mn3+4–xGa3+x]BO12, is realized for x ≥ 1. All samples demonstrate spin-glass-like magnetic properties, and th...
- Published
- 2019
14. Crystal structure and magnetic properties of A-site-ordered quadruple perovskite CeCu3Cr4O12
- Author
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Yoshio Katsuya, Alexei A. Belik, Kazunari Yamaura, and Masahiko Tanaka
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Materials science ,Mechanical Engineering ,Metals and Alloys ,Charge density ,Disproportionation ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Bond length ,Crystallography ,Mechanics of Materials ,Oxidation state ,Ferrimagnetism ,Materials Chemistry ,0210 nano-technology ,Powder diffraction ,Perovskite (structure) - Abstract
A-site-ordered quadruple perovskite CeCu3Cr4O12 was prepared by a high-pressure, high-temperature method at 7.7 GPa and about 1670 K. Its crystal structure was investigated using synchrotron X-ray powder diffraction between 100 and 590 K. In this temperature range, it crystallizes in the parent cubic structure for A-site-ordered quadruple perovskites with space group Im-3. It exhibits a ferrimagnetic transition at TC = 333 K. Very small changes of Cu O and Cr O bond lengths were found at TC, and no changes in Ce O bond lengths. Ce O bond lengths of CeCu3Cr4O12 (about 2.525 A at 290 K) were very close to those of CeCu3Mn4O12 and CeCu3Fe4O12 suggesting the Ce4+ oxidation state and the charge distribution as Ce4+Cu2+3Cr3.5+4O12. No intersite charge transfer or charge disproportionation transitions were found in CeCu3Cr4O12.
- Published
- 2019
15. Crystal structures of cation non-stoichiometric RMn3O6 (R = Gd, Er, and Tm) manganites belonging to A-site columnar-ordered quadruple perovskite family
- Author
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Masahiko Tanaka, Yoshio Katsuya, Alexei A. Belik, Kazunari Yamaura, Lei Zhang, and Yoshitaka Matsushita
- Subjects
Materials science ,Doping ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,Manganese ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,A-site ,Charge ordering ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,0210 nano-technology ,Stoichiometry ,Powder diffraction ,Perovskite (structure) - Abstract
High-pressure RMn3O6 manganites (belonging to a family of A-site columnar-ordered quadruple perovskites A2A′A″B4O12, where A′ is a site with a square-planar coordination and A″ is a site with a tetrahedral coordination) are prone to cation non-stoichiometry: they are rare-earth-deficient, R1−xMn3+xO6, for R = Ho, Y, Er, and Tm and manganese-deficient, R1+xMn3−xO6, for R = Gd. Here we investigated their crystal structures using single-crystal X-ray diffraction and synchrotron X-ray powder diffraction at room temperature. We found that the rare-earth deficiency is formed by doping of Mn2+ into the A site: [Er3+1.78Mn2+0.22]A[Mn3+]A′[Mn2+]A′′[Mn3+2]B1[Mn3.61+2]B2O12. The manganese deficiency is realized through doping of a small amount of Gd3+ into the A″ site: [Gd3+2]A[Mn3+]A′[Mn2+0.87Gd3+0.13]A′′[Mn3+2]B1[Mn3.44+2]B2O12. They all crystallize in space group Pmmn with layered charge ordering at the B sites. They are structurally related to CaFeTi2O6. Cation non-stoichiometry is supported by variations of the oxidation states of manganese at one of the B sites.
- Published
- 2019
16. Crystal structure, dielectric, and optical properties of β-calcium orthophosphates heavily doped with ytterbium
- Author
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Alexey V. Ishchenko, Ivan I. Leonidov, Bogdan I. Lazoryak, Sergey Yu. Stefanovich, Vladimir A. Morozov, Dina V. Deyneko, Evgeniya S. Zhukovskaya, Alexei A. Belik, and O. V. Baryshnikova
- Subjects
Ytterbium ,Phase transition ,Materials science ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,Differential scanning calorimetry ,chemistry ,Mechanics of Materials ,Materials Chemistry ,0210 nano-technology ,Luminescence ,Solid solution - Abstract
Solid solution of Ca10.5–1.5xYbx(PO4)7 (0 ≤ x ≤ 1) was synthesized in the β-Са3(РО4)2-type structure by a standard solid-state method. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements showed the presence of a reversible first-order phase transition of ferroelectric type between the room-temperature polar R3c structure to centrosymmetry. The temperature of the phase transition decreases from 1203 K for x = 0 to 788 K for x = 1, while the second-harmonic generation response decreases from 1.4 to 0.17 α-SiO2 powder standard units. The luminescence spectra of Ca10.5–1.5xYbx(PO4)7 point to two structural Yb3+ positions in full agreement with the structural data. The intensity of the luminescence emission line at ∼975 nm due to the 2F5/2 → 2F7/2 transition reaches the maximum at x = 0.667 in Ca10.5–1.5xYbx(PO4)7. The Yb3+ luminescence spectra studied as a function of the chemical composition 0
- Published
- 2019
17. High-pressure synthesis, crystal structure, and magnetic properties of hexagonal Ba3CuOs2O9
- Author
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Yoshitaka Matsushita, Rongfu Zhou, Weijie Zhou, Yoshihiro Tsujimoto, Jie Chen, Masahiko Tanaka, Kazunari Yamaura, Meixia Wu, Yoshio Katsuya, Man-Rong Li, Hongbin Liang, Martin Jansen, Lirong Zheng, Alexei A. Belik, and Hai L. Feng
- Subjects
Materials science ,Transition temperature ,02 engineering and technology ,Crystal structure ,Coercivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,Ferrimagnetism ,Phase (matter) ,Materials Chemistry ,Ceramics and Composites ,Antiferromagnetism ,Orthorhombic crystal system ,Physical and Theoretical Chemistry ,0210 nano-technology ,Perovskite (structure) - Abstract
A new polymorph of the triple perovskite Ba3CuOs2O9, which usually exists in the orthorhombic phase, was synthesized under high-pressure and high-temperature conditions at 6 GPa and 1100 °C. Under the synthetic condition, Ba3CuOs2O9 crystallizes into a hexagonal structure (P63/mmc) with a = 5.75178(1) A and c = 14.1832(1) A, and undergoes a 1.36% increment in density, compared to that of the orthorhombic phase. Although Ba3CuOs2O9 maintains its 6 H perovskite-type structure, the distribution of Cu and Os atoms are dramatically altered; (Cu)4a(Os,Os)8f transits to (Os)2a(Cu,Os)4f ordering over the corner- and face-sharing sites, respectively. The hexagonal Ba3CuOs2O9 exhibits a ferrimagnetic transition at 290 K, which is in stark contrast to the antiferromagnetic transition at 47 K exhibited by the orthorhombic Ba3CuOs2O9. The enhanced transition temperature is most likely due to the strongly antiferromagnetic Os5+–O–Os5+ bonds and the moderately antiferromagnetic Os5+–O–Cu2+ bonds, the angles of which are both approximately 180°. The 290 K ferrimagnetic transition temperature is the highest reported for triple-perovskite osmium oxides. Besides, the coercive field is greater than 70 kOe at 5 K, which is remarkable among the coercive fields of magnetic oxides.
- Published
- 2019
18. Structural and Magnetic Phase Transitions in BiFe1 − xMnxO3 Solid Solution Driven by Temperature
- Author
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Dmitry V. Karpinsky, Maxim V. Silibin, Siarhei I. Latushka, Dmitry V. Zhaludkevich, Vadim V. Sikolenko, Hanan Al-Ghamdi, Aljawhara H. Almuqrin, M. I. Sayyed, and Alexei A. Belik
- Subjects
General Chemical Engineering ,General Materials Science ,crystal structure ,magnetic state ,multiferroics ,phase transitions ,magnetometry ,X-ray diffraction ,synchrotron diffraction - Abstract
The crystal structure and magnetic state of the (1 − x)BiFeO3-(x)BiMnO3 solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the room-temperature structural transitions from the polar-active rhombohedral phase to the antipolar orthorhombic phase, and then to the monoclinic phase accompanied by the formation of two-phase regions consisting of the adjacent structural phases in the concentration ranges 0.25 < x1 < 0.30 and 0.50 ≤ x2 < 0.65, respectively. The accompanied changes in the magnetic structure refer to the magnetic transitions from the modulated antiferromagnetic structure to the non-colinear antiferromagnetic structure, and then to the orbitally ordered ferromagnetic structure. The compounds with a two-phase structural state at room temperature are characterized by irreversible temperature-driven structural transitions, which favor the stabilization of high-temperature structural phases. The magnetic structure of the compounds also exhibits an irreversible temperature-induced transition, resulting in an increase of the contribution from the magnetic phase associated with the high-temperature structural phase. The relationship between the structural parameters and the magnetic state of the compounds with a metastable structure is studied and discussed depending on the chemical composition and heating prehistory.
- Published
- 2022
19. Temperature-Driven Transformation of the Crystal and Magnetic Structures of BiFe 0.7 Mn 0.3 O 3 Ceramics.
- Author
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Karpinsky, Dmitry V., Silibin, Maxim V., Latushka, Siarhei I., Zhaludkevich, Dmitry V., Sikolenko, Vadim V., Svetogorov, Roman, Sayyed, M. I., Almousa, Nouf, Trukhanov, Alex, Trukhanov, Sergei, and Belik, Alexei А.
- Subjects
MAGNETIC structure ,MAGNETIC crystals ,CRYSTAL structure ,NEUTRON diffraction ,PHASE transitions ,DIFFERENTIAL thermal analysis - Abstract
The compound BiFe
0.7 Mn0.3 O3 consisting at room temperature of coexistent anti-polar orthorhombic and polar rhombohedral phases has a metastable structural state, which has been studied by laboratory X-ray, synchrotron and neutron diffraction, magnetometry, differential thermal analysis, and differential scanning calorimetry. Thermal annealing of the sample at temperatures above the temperature-driven phase transition into the single phase rhombohedral structure (~700 K) causes an increase of the volume fraction of the rhombohedral phase at room temperature from ~10% up to ~30%, which is accompanied by the modification of the magnetic state, leading to strengthening of a ferromagnetic component. A strong external magnetic field (~5 T) applied to the sample notably changes its magnetic properties, as well as provides a reinforcement of the ferromagnetic component, thus leading to an interaction between two magnetic subsystems formed by the antiferromagnetic matrix with non-collinear alignment of magnetic moments and the nanoscale ferromagnetic clusters coexisting within it. The modification of the structural state and magnetic properties of the compounds and a correlation between different structural and magnetic phases are discussed focusing on the effect of thermal annealing and the impact of an external magnetic field. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
20. Structural and Magnetic Phase Transitions in BiFe 1 − x Mn x O 3 Solid Solution Driven by Temperature.
- Author
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Karpinsky, Dmitry V., Silibin, Maxim V., Latushka, Siarhei I., Zhaludkevich, Dmitry V., Sikolenko, Vadim V., Al-Ghamdi, Hanan, Almuqrin, Aljawhara H., Sayyed, M. I., and Belik, Alexei A.
- Abstract
The crystal structure and magnetic state of the (1 − x)BiFeO
3 -(x)BiMnO3 solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the room-temperature structural transitions from the polar-active rhombohedral phase to the antipolar orthorhombic phase, and then to the monoclinic phase accompanied by the formation of two-phase regions consisting of the adjacent structural phases in the concentration ranges 0.25 < x1 < 0.30 and 0.50 ≤ x2 < 0.65, respectively. The accompanied changes in the magnetic structure refer to the magnetic transitions from the modulated antiferromagnetic structure to the non-colinear antiferromagnetic structure, and then to the orbitally ordered ferromagnetic structure. The compounds with a two-phase structural state at room temperature are characterized by irreversible temperature-driven structural transitions, which favor the stabilization of high-temperature structural phases. The magnetic structure of the compounds also exhibits an irreversible temperature-induced transition, resulting in an increase of the contribution from the magnetic phase associated with the high-temperature structural phase. The relationship between the structural parameters and the magnetic state of the compounds with a metastable structure is studied and discussed depending on the chemical composition and heating prehistory. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
21. High-Pressure Synthesis, Crystal Structure, and Semimetallic Properties of HgPbO3
- Author
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Jie Chen, Yoshitaka Matsushita, Kazunari Yamaura, Youguo Shi, Yu Su, Alexei A. Belik, Taras Kolodiazhnyi, Yoshihiro Tsujimoto, Yoshio Katsuya, and Masahiko Tanaka
- Subjects
Chemistry ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic susceptibility ,Heat capacity ,Inorganic Chemistry ,Crystallography ,Magnetization ,Electrical resistivity and conductivity ,Hall effect ,0103 physical sciences ,Diamagnetism ,Crystallite ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology - Abstract
The crystal structure of HgPbO3 was studied using single-crystal X-ray diffraction and powder synchrotron X-ray diffraction. The structure was well characterized as a centrosymmetric model with a space group of R-3m [hexagonal setting: a = 5.74413(6) A and c = 7.25464(8) A] rather than as a noncentrosymmetric model as was expected. It was found that Pb4+ is octahedrally coordinated by six oxygen atoms as usual, while Hg2+ is coordinated by three oxygen atoms in a planar manner, this being a very rare coordination of Hg in a solid-state material. The magnetic and electronic transport properties were investigated in terms of the magnetic susceptibility, magnetization, Hall coefficient, and specific heat capacity of polycrystalline HgPbO3. Although HgPbO3 has a carrier concentration (=7.3–8.5 × 1020 cm–3) that is equal to that of metallic oxides, the very weak temperature dependence of the electrical resistivity (residual-resistivity ratio ∼1.5), the significant diamagnetism (= –1.02 × 10–4 emu mol–1 at 300 ...
- Published
- 2018
22. Influence of magnesium on dielectric properties of Ca 9–x Mg x Bi(VO 4 ) 7 ceramics
- Author
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Dina V. Deyneko, Sergey Yu. Stefanovich, Evgeniya S. Zhukovskaya, O. V. Baryshnikova, Bogdan I. Lazoryak, Vladimir A. Morozov, Alexei A. Belik, Nikolai G. Dorbakov, Vadim V. Grebenev, and Vladimir V. Titkov
- Subjects
Materials science ,Magnesium ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry ,visual_art ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Ceramic ,Composite material ,0210 nano-technology - Published
- 2018
23. Mn Self-Doping of Orthorhombic RMnO3 Perovskites: (R0.667Mn0.333)MnO3 with R = Er–Lu
- Author
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Alexei A. Belik, Kazunari Yamaura, Lei Zhang, Yoshio Katsuya, Shigenori Ueda, D. Gerlach, Masahiko Tanaka, Andreas Dönni, and Toyohiro Chikyow
- Subjects
Chemistry ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,Magnetization ,X-ray photoelectron spectroscopy ,Oxidation state ,Ferrimagnetism ,Antiferromagnetism ,Orthorhombic crystal system ,Physical and Theoretical Chemistry ,Isostructural ,0210 nano-technology - Abstract
Orthorhombic rare-earth trivalent manganites RMnO3 (R = Er-Lu) were self-doped with Mn to form (R0.667Mn0.333)MnO3 compositions, which were synthesized by a high-pressure, high-temperature method at 6 GPa and about 1670 K from R2O3 and Mn2O3. The average oxidation state of Mn is 3+ in (R0.667Mn0.333)MnO3. However, Mn enters the A site in the oxidation state of 2+, creating the average oxidation state of 3.333+ at the B site. The presence of Mn2+ was confirmed by hard X-ray photoelectron spectroscopy measurements. Crystal structures were studied by synchrotron powder X-ray diffraction. (R0.667Mn0.333)MnO3 crystallizes in space group Pnma with a = 5.50348(2) A, b = 7.37564(1) A, and c = 5.18686(1) A for (Lu0.667Mn0.333)MnO3 at 293 K, and they are isostructural with the parent RMnO3 manganites. Compared with RMnO3, (R0.667Mn0.333)MnO3 exhibits enhanced Neel temperatures of about TN1 = 106-110 K and ferrimagnetic or canted antiferromagnetic properties. Compounds with R = Er and Tm show additional magnetic transitions at about TN2 = 9-16 K. (Tm0.667Mn0.333)MnO3 exhibits a magnetization reversal or negative magnetization effect with a compensation temperature of about 16 K.
- Published
- 2018
24. Enhanced nonlinear optical activity and Ca2+-conductivity in Са10.5-Pb (VO4)7 ferroelectrics
- Author
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Dina V. Deyneko, D. A. Petrova, Dmitry A. Belov, Oksana V. Barishnikova, Alexei A. Belik, E. A. Fortalnova, Bogdan I. Lazoryak, Vladimir A. Morozov, and Sergey Yu. Stefanovich
- Subjects
Phase transition ,Materials science ,Mechanical Engineering ,Metals and Alloys ,Mineralogy ,02 engineering and technology ,Dielectric ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,Crystallography ,Mechanics of Materials ,Differential thermal analysis ,Materials Chemistry ,Ionic conductivity ,0210 nano-technology ,Powder diffraction ,Solid solution - Abstract
Са3(VO4)2-based compositions are considered as promising multifunctional materials combining ferroelectric, optical nonlinear, and Ca2+-ion conductive properties. Their ferroelectric Curie points stretch from minimal for β-Ca3(PO4)2-type compounds temperatures of about 800 K to very high. Investigated in this paper lead substitution for calcium is as a factor controlling ferroelectricity, ionic-conductivity and non-linear optical activity in Ca3(VO4)2-based materials. Polar phase containing powders and ceramics in Ca10.5-xPbx(VO4)7 system are synthesized for 0 ≤ x ≤ 9.5 by the solid state method, and structurally characterized with X-ray powder diffraction and transmission electron microscopy. Dielectric properties, differential thermal analysis and second harmonic generation (SHG) evidence that Ca10.5-xPbx(VO4)7 solid solution (0 ≤ x ≤ 4.5) belongs to whitlockite-type ferroelectrics. SHG activity strongly increases with x up to its maximum at x = 4.5, where it has a record value among all studied before Ca3(XO4)2-related compounds (X = P,V). Ferroelectric Curie temperatures of Ca3(VO4)2 drops from its known value Tc = 1368 K (x = 0) to 770 K (x = 4.5). Crystal symmetry at Tc changes from R3c to R 3 ¯ c . After this, one more phase transition to the symmetry R 3 ¯ m takes place, its temperature bringing down from 1387 K (x = 0) to 804 K (x = 4.5). Ferroelectric and non-ferroelectric phase transitions in the Са10.5-xPbx(VO4)7 are separated by a broad interval Δ T = 20–50 K and both classified as first-order transformations going in the sequence: R3c↔ R 3 ¯ c ↔ R 3 ¯ m . Structures of Са10.5-xPbx(VO4)7 compositions with x = 0.5–4 were refined by the Rietveld method and peculiarities of the Pb2+cations distribution in the M1 - M3 and M4 sites of β-Ca3(PO4)2-type structure are discussed regarding the optical nonlinear, ferroelectric and ion-conductive properties. Manifold increased Ca2+- ion conductivity of Са10.5-xPbx(VO4)7 in vicinity of 1000 K at x = 4–4.5 in combination with their ferroelectric and optical nonlinear properties extends applicability of ion-exchange technologies to new promising materials.
- Published
- 2018
25. Crystal structure, dielectric and optical properties of β-Ca3(PO4)2-type phosphates Ca9-Zn La(PO4)7:Ho3+
- Author
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O. V. Baryshnikova, Kirill N. Boldyrev, Yu. Yu. Dikhtyar, Dina V. Deyneko, V.А. Morozov, А.А. Belik, and Bogdan I. Lazoryak
- Subjects
Materials science ,Biophysics ,Phosphor ,02 engineering and technology ,General Chemistry ,Crystal structure ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Dielectric spectroscopy ,Crystal ,Crystallography ,Differential scanning calorimetry ,0210 nano-technology ,Spectroscopy ,Luminescence - Abstract
A series of new phosphates Ca9-xZnxLa(PO4)7:Ho3+ with the β-Ca3(PO4)2-type structure was synthesized by the solid state route. An intense near infra-red (NIR) emission according to intraconfigural 4f-4f transitions of Ho3+ ions 5I7 – 5I8 (~2 μm) and 5I6 – 5I8 (~1.156 μm) was observed. The obtained phases were studied by a combination of methods including synchrotron powder X-ray diffraction, dielectric spectroscopy, second harmonic generation, differential scanning calorimetry, luminescence spectroscopy. The structure of Ca8ZnLa(PO4)7 was refined by the Rietveld method in centrosymmetric space group R 3 ‾ c. The Ca2+ → Zn2+ substitution in the M5 site leads to a transformation from polar R3c space group (x = 0 – 0.5) to centrosymmetric R 3 ‾ c space group (x = 0.6–1) and to the increased integral intensity of luminescence with maxima at x = 1. It was concluded that the crystal site engineering in the Ho3+-containing β-Ca3(PO4)2-type hosts offers a promising way to obtain new NIR phosphors for use in the creation of biocompatible bone tissue fillers.
- Published
- 2021
26. Tuning of nonlinear optical and ferroelectric properties via the cationic composition of Ca9.5–1.5Bi Cd(VO4)7 solid solutions
- Author
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Alexei A. Belik, Vladimir A. Morozov, O. V. Baryshnikova, Bogdan I. Lazoryak, Nikolai G. Dorbakov, S. Yu. Stefanovich, Masahiko Tanaka, and Yoshio Katsuya
- Subjects
Diffraction ,Phase transition ,Materials science ,Mechanical Engineering ,Analytical chemistry ,Second-harmonic generation ,02 engineering and technology ,Dielectric ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,Crystallography ,Mechanics of Materials ,lcsh:TA401-492 ,lcsh:Materials of engineering and construction. Mechanics of materials ,General Materials Science ,0210 nano-technology ,Order of magnitude ,Solid solution - Abstract
Ca9.5–1.5xBixCd(VO4)7 (0 ≤ x ≤ 1) solid solutions with the whitlockite-type structure (SG R3c) were synthesized by a standard solid-state method in air. Structures of Ca9.5–1.5xBixCd(VO4)7 (x = 0.167, 0.5, 0.833) were refined by the Rietveld method from synchrotron powder X-ray diffraction data. Nonlinear optical properties of the whitlockite-type compounds can be designed and increased by an order of magnitude through appropriate isovalent and aliovalent substitutions for Ca2+ cations. Dielectric and temperature second harmonic generation investigations revealed the presence of a reversible ferroelectric phase transition in the range from 1331 K to 1055 K. The phase transition temperature monotonically decreases while nonlinear optical activity of Ca9.5–1.5xBixCd(VO4)7 strongly increases with increasing Bi3+ content. Keywords: Vanadates, Ferroelectric properties, Nonlinear optical properties, Crystal structure
- Published
- 2017
27. Structural, magnetic, and dielectric properties of solid solutions between BiMnO3 and YMnO3
- Author
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Alexei A. Belik
- Subjects
Magnetic structure ,Chemistry ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,0103 physical sciences ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Antiferromagnetism ,Multiferroics ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology ,Néel temperature ,Powder diffraction ,Solid solution - Abstract
Bi 1− x Y x MnO 3 (0.1≤ x ≤0.9) solid solutions were prepared by the high-pressure high-temperature method at 6 GPa and 1573 K. They crystallize in the GdFeO 3 -type perovskite structure with the Pnma symmetry. Crystal structures of Bi 0.9 Y 0.1 MnO 3 and Bi 0.5 Y 0.5 MnO 3 are studied by synchrotron X-ray powder diffraction at room temperature. Only one Neel temperature, T N , is found in samples with 0.1≤ x ≤0.9 in comparison with two Neel temperatures observed in YMnO 3 ( T N =29 and 39 K). Samples with 0.5≤ x ≤0.9 have almost constant T N =44 K, while T N starts to increase linearly for other compositions: T N =46 K for x =0.3, T N =58 K for x =0.2, and T N =68 K for x =0.1. Field-induced transitions from canted-antiferromagnetic states to antiferromagnetic states are detected at about 30 kOe for x =0.2 and 70 kOe for x =0.1. Dielectric constant increases below T N in samples with 0.5≤ x ≤1, while it decreases below T N in samples with 0.1≤ x ≤0.3. Our data suggest that a magnetic structure changes near x =0.4. By extrapolation, we could estimate lattice parameters ( a =5.9221 A, b =7.5738 A, and c =5.4157 A) and T N =79 K for a hypothetical Pnma modification of BiMnO 3 .
- Published
- 2017
28. Changes in spin and lattice dynamics induced by magnetic and structural phase transitions in multiferroic SrMn7O12
- Author
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Jakub Vit, Stanislav Kamba, Filip Kadlec, Christelle Kadlec, Alexei A. Belik, Veronica Goian, I. S. Glazkova, F. Borodavka, and Dmitry Nuzhnyy
- Subjects
Physics ,Condensed matter physics ,Phonon ,Resonance ,Charge (physics) ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Spectral line ,Condensed Matter::Materials Science ,0103 physical sciences ,Multiferroics ,010306 general physics ,0210 nano-technology ,Spin (physics) - Abstract
${\mathrm{SrMn}}_{7}{\mathrm{O}}_{12}$ is a recently synthesized homolog of multiferroic ${\mathrm{CaMn}}_{7}{\mathrm{O}}_{12}$. Upon cooling, ${\mathrm{SrMn}}_{7}{\mathrm{O}}_{12}$ undergoes a series of structural and magnetic phase transitions from cubic to rhombohedral symmetry, and to an incommensurately modulated crystal structure, which is connected with charge and orbital ordering of the Mn cations. We report infrared, terahertz, and Raman spectra of ${\mathrm{SrMn}}_{7}{\mathrm{O}}_{12}$ ceramics reflecting corresponding changes in phonon selection rules, including new phonons appearing in spin-order-induced ferroelectric phases. The observed phonon activities are compared with the predictions from the factor-group analysis. In the high-temperature phase, more phonons are observed than the number predicted for the cubic symmetry. This is explained by the presence of rhombohedral clusters in the cubic phase. The strongest variations occur in THz spectra near the two magnetic phase transitions, at ${T}_{\mathrm{N}1}=87\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and ${T}_{\mathrm{N}2}=63\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. These activate new modes in the spectra, with resonance frequencies and intensities changing with temperature and magnetic field. Below ${T}_{\mathrm{N}2}$, we observed a transfer of oscillator strengths from low-frequency phonons to these excitations, which we assign to electromagnons.
- Published
- 2019
29. New type of borophosphate anionic radical in the crystal structure of CsAl2BP6O20
- Author
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Olga V. Yakubovich, Larisa Shvanskaya, and V. I. Belik
- Subjects
Diffraction ,010405 organic chemistry ,Chemistry ,Inorganic chemistry ,Cationic polymerization ,chemistry.chemical_element ,General Chemistry ,Crystal structure ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Crystallography ,Octahedron ,law ,Group (periodic table) ,Caesium ,Tetrahedron ,General Materials Science ,Crystallization - Abstract
The crystal structure of a new borophosphate CsAl2BP6O20 obtained by spontaneous crystallization in a multicomponent Cs–Cu–B–P–O system is determined by X-ray diffraction (a = 11.815(2), b = 10.042(2), and c = 26.630(4) A; space group Pbca, Z = 8, V = 3159.5(10) A3; R1 = 0.043). A new type of borophosphate anionic 2D radical characterized by the lowest B: P = 1: 6 ratio and containing P3O10 phosphate groups is found in the compound. A mixed-type anionic framework consisting of vertex-sharing BO4 and PO4 tetrahedra and AlO6 octahedra is distinguished in the structure. Large cesium atoms are located in the channels of the framework. Topological relationships are revealed between the structures of the CsAl3(P3O10)2 and CsAl2BP6O20 phases having different cationic compositions. These compounds can be considered quasi-polytypic phases.
- Published
- 2016
30. Local crystal structure of multiferroic BiMnO3 studied by 57Fe probe Mössbauer spectroscopy
- Author
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Ya. S. Glazkova, Igor A. Presniakov, A. A. Belik, and Alexey V. Sobolev
- Subjects
Materials science ,Condensed matter physics ,General Chemical Engineering ,Metals and Alloys ,Crystal structure ,Atmospheric temperature range ,010402 general chemistry ,Manganite ,01 natural sciences ,0104 chemical sciences ,Ion ,Inorganic Chemistry ,High pressure ,0103 physical sciences ,Mössbauer spectroscopy ,Materials Chemistry ,Mossbauer spectra ,Multiferroics ,010306 general physics - Abstract
This paper presents a 57Fe probe Mossbauer spectroscopy study of a BiMn0.9657Fe0.04O3 manganite synthesized at high pressure (6 GPa). The BiMnO3 manganite possesses multiferroic properties and exhibits cooperative orbital ordering due to Jahn–Teller active Mn3+ ions. 57Fe Mossbauer spectra have been measured and analyzed in a wide temperature range, which includes the orbital ordering temperature of BiMnO3.
- Published
- 2016
31. LiNbO3-Type Oxide (Tl1–xScx)ScO3: High-Pressure Synthesis, Crystal Structure, and Electronic Properties
- Author
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Fumiyasu Oba, Alexei A. Belik, Masahiko Tanaka, Wei Yi, Yoshio Katsuya, and Yu Kumagai
- Subjects
Chemistry ,Oxide ,02 engineering and technology ,Crystal structure ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Polarization density ,chemistry.chemical_compound ,Crystallography ,Lattice (order) ,Physical and Theoretical Chemistry ,0210 nano-technology ,Powder diffraction ,Stoichiometry ,Ambient pressure - Abstract
We investigate the synthesis of a thallium scandate, TlScO3, under high-pressure (6-7.7 GPa) and high-temperature (1373-1773 K) conditions. At 6 GPa, a LiNbO3-type phase appears in a narrow temperature range and in mixtures with other phases. At 7.7 GPa and 1673 K, a new LiNbO3-type oxide is found with a composition of (Tl(1-x)Sc(x))ScO3 and x ≈ 0.26 as determined by structural analysis from X-ray powder diffraction data. It crystallizes in space group R3c (No. 161) with lattice parameters of a = 5.50283(7) Å and c = 14.4606(2) Å. It is stable at least up to 800 K at ambient pressure. The point-charge model gives an electric polarization of 60 μC/cm(2). First-principles calculations show that centrosymmetric ilmenite-type and polar LiNbO3-type structures of stoichiometric TlScO3 have almost the same lowest energy, and the next stable structure is a GdFeO3-type perovskite structure.
- Published
- 2016
32. High-pressure synthesis, crystal structures, and magnetic and dielectric properties of GdFeO3-type perovskites (Dy0.5Mn0.5)(Mn1−Ti )O3 with x = 0.5 and 0.75
- Author
-
Alexei A. Belik, Ran Liu, Masahiko Tanaka, and Kazunari Yamaura
- Subjects
Materials science ,Mechanical Engineering ,Metals and Alloys ,02 engineering and technology ,Crystal structure ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Synchrotron ,0104 chemical sciences ,law.invention ,Crystallography ,Mechanics of Materials ,law ,Ferrimagnetism ,High pressure ,Materials Chemistry ,0210 nano-technology ,Powder diffraction ,Perovskite (structure) ,Solid solution - Abstract
(Dy0.5Mn0.5)(Mn1−xTix)O3 perovskite solid solutions with x = 0.5 and 0.75 were prepared by a high-pressure high-temperature method at 6 GPa and about 1570–1670 K. They have a GdFeO3-type perovskite structure with Pnma space group and random distributions of Dy3+ and Mn2+ cations at the A site, and Mn3+/2+ and Ti4+ cations at the B site. Their crystal structures were investigated using synchrotron X-ray powder diffraction at room temperature. The x = 0.5 sample shows a ferrimagnetic transition below TC = 50 K and dielectric constant of about 25 between 10 and 150 K. The x = 0.75 sample shows a ferrimagnetic-like transition below TC = 20 K and temperature-independent dielectric constant of about 100 between 10 and 250 K.
- Published
- 2020
33. Magnetic structures of the rare-earth quadruple perovskite manganites RMn7O12
- Author
-
Alexei A. Belik, Dmitry D. Khalyavin, Pascal Manuel, Lei Zhang, Kazunari Yamaura, and R. D. Johnson
- Subjects
Physics ,Magnetism ,Order (ring theory) ,chemistry.chemical_element ,02 engineering and technology ,Crystal structure ,Manganese ,021001 nanoscience & nanotechnology ,01 natural sciences ,Condensed Matter::Materials Science ,Magnetization ,Crystallography ,chemistry ,Formula unit ,0103 physical sciences ,Perovskite manganites ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin canting - Abstract
We report a neutron powder diffraction study of $R{\mathrm{Mn}}_{7}{\mathrm{O}}_{12}$ quadruple perovskite manganites with $R=\mathrm{La}$, Ce, Nd, Sm, and Eu. We show that in all measured compounds concomitant magnetic ordering of the $A$ and $B$ manganese sublattices occurs on cooling below the N\'eel temperature. The respective magnetic structures are collinear, with one uncompensated ${\mathrm{Mn}}^{3+}$ moment per formula unit as observed in bulk magnetization measurements. We show that both ${\mathrm{LaMn}}_{7}{\mathrm{O}}_{12}$ and ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$ undergo a second magnetic phase transition at low temperature, which introduces a canting of the $B$-site sublattice moments that is commensurate in ${\mathrm{LaMn}}_{7}{\mathrm{O}}_{12}$ and incommensurate in ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$. This spin canting is consistent with a magnetic instability originating in the $B$-site orbital order. Furthermore, ${\mathrm{NdMn}}_{7}{\mathrm{O}}_{12}$ displays a third magnetic phase transition at which long-range ordering of the Nd sublattice modifies the periodicity of the incommensurate spin canting. Our results demonstrate a rich interplay between transition-metal magnetism, orbital order, and the crystal lattice, which may be fine-tuned by cation substitution and rare-earth magnetism.
- Published
- 2018
34. Synthesis, structure, and magnetic and dielectric properties of magnetoelectric BaDyFeO4 ferrite
- Author
-
Alexei A. Belik, Igor A. Presniakov, I. S. Glazkova, Noriki Terada, Kazunari Yamaura, Masahiko Tanaka, Yoshio Katsuya, and Alexey V. Sobolev
- Subjects
Materials science ,Condensed matter physics ,Mechanical Engineering ,Multiferroics ,Crystal structure ,Metals and Alloys ,02 engineering and technology ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,Magnetic field ,Pyroelectricity ,Magnetodielectric effect ,Mechanics of Materials ,Materials Chemistry ,Ferrite (magnet) ,Ferrites ,Isostructural ,0210 nano-technology - Abstract
BaDyFeO4 was prepared by a conventional solid-state method in air at 1573 K. It crystallizes in space group Pnma (No. 62) with a = 13.16861(1) angstrom, b = 5.70950(1) angstrom, and c = 10.26783(1) angstrom, and it is isostructural with BaYFe0 4 . Three magnetic transitions were found in BaDyFeO4 at T-N3 = 9 K, T-N2 = 23 K, and T-N1 =47 K in zero magnetic field in comparison with two magnetic transitions observed in BaYFeO4. Magnetic-field-induced transitions were also detected in BaDyFeO4 at 18 and 28 kOe (at T= 1.8 K). Frequency-dependent broad dielectric peaks were observed in BaDyFeO4 spanning between T-N2 and T-N and centred at 35 K - this temperature does not coincide with any T-N. No dielectric anomalies were found at T-N1 and T-N3, while very weak frequency-independent dielectric anomalies were detected at T-N2. Positive and negative magnetodielectric effects were measured in BaDyFeO4 (within a range of -0.8 and + 0.4% up to 90 kOe) reflecting magnetic-field dependence of dielectric constant. Pyroelectric current measurements did not detect any ferroelectricity in BaDyFeO4 under measurement conditions used. No dielectric anomalies and no magnetodielectric effects were found in BaYFeO4. (C) 2019 Elsevier B.V. All rights reserved.
- Published
- 2019
35. Isovalent and aliovalent cation substitutions in the anion sublattice of whitlockite-type ferroelectrics Ca9RE(VO4)7 with RE =Y and Yb
- Author
-
O. V. Baryshnikova, Sergey M. Aksenov, Dina V. Deyneko, Vladimir V. Titkov, Alexey A. Belik, Yury Yu. Dikhtyar, Sergey Yu. Stefanovich, and Bogdan I. Lazoryak
- Subjects
Materials science ,Photoluminescence ,chemistry.chemical_element ,Vanadium ,Germanium ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,Materials Chemistry ,Ceramic ,Physical and Theoretical Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Ferroelectricity ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Crystallography ,chemistry ,visual_art ,Ceramics and Composites ,visual_art.visual_art_medium ,0210 nano-technology ,Luminescence ,Solid solution - Abstract
A solid state route was used for the preparation of whitlockite-type solid solutions Ca9Y(NbO4)x(VO4)7–x and Ca9+0.5xYb (GeO4)x(VO4)7–х in both powder and ceramic forms. The complex of methods, including synchrotron powder diffraction were applied for the characterization of the first-time obtained compounds. The limits of the anionic substitution were found up to х = 0.28 (Nb) and 0.35 (Ge). The synthesized solid solutions show ferroelectric properties. The Curie temperatures Tc were determined and gradually rise with x. The increase of Tc correlates with the enlargement of tetrahedral units upon Nb5+ or Ge4+ substitutions for V5+ cations. The intensity of optical second harmonic generation (SHG) induced by a Nd:YAG laser depends non-monotonically on the grain size in powder Ca9Y(NbO4)x(VO4)7–x samples, marking the length of the phase matching lc = 15 μm for x = 0.28 in comparison with lc = 9.14 μm in Ca9Y(VO4)7. Manifold increase in the SHG intensity in both solid solutions is partly related to the appearance of more polarizable Nb5+ and Ge4+ cations in the E1O4 tetrahedra on the 3-fold axis, resulting in an enlarged birefringence of the materials. The photoluminescence study of the Ca9+0.5xYb(GeO4)x(VO4)7–х reveals the same environment of the Yb3+ ions all alone the solid solution. The intensity of the luminescence rises with germanium substitution for vanadium about 2 times.
- Published
- 2019
36. A novel red Ca8.5Pb0.5Eu(PO4)7 phosphor for light emitting diodes application
- Author
-
Vladimir A. Morozov, Dmitry A. Spassky, Joke Hadermann, Dina V. Deyneko, A.E. Savon, Alexei A. Belik, Sergey Yu. Stefanovich, and Bogdan I. Lazoryak
- Subjects
Phase transition ,Chemistry ,Physics ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,Phosphor ,Crystal structure ,Emission intensity ,Mechanics of Materials ,Materials Chemistry ,Emission spectrum ,Absorption (electromagnetic radiation) ,Luminescence ,Engineering sciences. Technology ,Solid solution - Abstract
Ca 9– x Pb x Eu(PO 4 ) 7 (0 ≤ x ≤ 1) solid solutions with a whitlockite-type (or β -Ca 3 (PO 4 ) 2 -type) structure (sp.gr. R 3 c ) were prepared by a standard solid-state method in air. Their luminescent properties under near-ultraviolet (n-UV) light were investigated. Excitation spectra of Ca 9– x Pb x Eu(PO 4 ) 7 showed the strongest absorption at about 395 nm, which matches well with commercially available n-UV-emitting GaN-based LED chips. Emission spectra indicated an intense red emission due to the 5 D 0 → 7 F 2 transition of Eu 3+ , with a maximum in the intensity for Ca 8.5 Pb 0.5 Eu(PO 4 ) 7 . The emission intensity of Ca 8.5 Pb 0.5 Eu(PO 4 ) 7 was about 1.8 times higher than that of a Ca 9 Eu(PO 4 ) 7 phosphor. We suggest that the introduction of Pb 2+ is an efficient approach to enhance luminescence properties of such phosphors. We clarified the influence of the Ca 2+ → Pb 2+ substitution on intensities of three bands for the 5 D 0 → 7 F 0 transition in excitation spectra of Ca 9– x Pb x Eu(PO 4 ) 7 . In addition, we found a reversible first-order phase transition from R 3 ≿ to R 3 ¯ ≿ symmetry by second-harmonic generation in the range from 753 K ( x = 1) to 846 K ( x = 0).
- Published
- 2015
37. High-Pressure Synthesis, Crystal Structures, and Properties of CdMn7O12 and SrMn7O12 Perovskites
- Author
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Alexey V. Sobolev, Yoshitaka Matsushita, Noriki Terada, Yoshio Katsuya, Igor A. Presniakov, Masahiko Tanaka, Alexei A. Belik, and Yana S. Glazkova
- Subjects
Inorganic Chemistry ,Charge ordering ,Crystallography ,Chemistry ,High pressure ,Lattice (order) ,Mössbauer spectroscopy ,Dielectric ,Crystal structure ,Physical and Theoretical Chemistry ,Isostructural ,Ferroelectricity - Abstract
We synthesize CdMn7O12 and SrMn7-xFexO12 (x = 0, 0.08, and 0.5) perovskites under high pressure (6 GPa) and high temperature (1373-1573 K) conditions and investigate their structural, magnetic, dielectric, and ferroelectric properties. CdMn7O12 and SrMn7O12 are isostructural with CaMn7O12: space group R3̅ (No. 148), Z = 3, and lattice parameters a = 10.45508(2) Å and c = 6.33131(1) Å for CdMn7O12 and a = 10.49807(1) Å and c = 6.37985(1) Å for SrMn7O12 at 295 K. There is a structural phase transition at 493 K in CdMn7O12 and at 404 K in SrMn7O12 to a cubic structure (space group Im3̅), associated with charge ordering as found by the structural analysis and Mössbauer spectroscopy. SrMn6.5Fe0.5O12 crystallizes in space group Im3̅ at 295 K with a = 7.40766(2) Å and exhibits spin-glass magnetic properties below 34 K. There are two magnetic transitions in CdMn7O12 with the Néel temperatures TN2 = 33 K and TN1 = 88 K, and in SrMn7O12 with TN2 = 63 K and TN1 = 87 K. A field-induced transition is found in CdMn7O12 from about 65 kOe, and TN2 = 58 K at 90 kOe. No dielectric anomalies are found at TN1 and TN2 at 0 Oe in both compound, but CdMn7O12 exhibits small anomalies at TN1 and TN2 at 90 kOe. In pyroelectric current measurements, we observe large and broad peaks around magnetic phase transition temperatures in CdMn7O12, SrMn7O12, and SrMn6.5Fe0.5O12; we assign those peaks to extrinsic effects and compare our results with previously reported results on CaMn7O12. We also discuss general tendencies of the AMn7O12 perovskite family (A = Cd, Ca, Sr, and Pb).
- Published
- 2015
38. High-pressure synthesis, crystal structure and magnetic properties of TlCrO3 perovskite
- Author
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Igor A. Presniakov, Kazunari Yamaura, Yasutaka Imanaka, Shigeki Nimori, Wei Yi, Yana S. Glazkova, Alexei A. Belik, Kanji Takehana, Yoshio Katsuya, Yoshitaka Matsushita, Yoshihiro Tsujimoto, Naohito Tsujii, Yuliya O. Lekina, and Alexey V. Sobolev
- Subjects
Inorganic Chemistry ,Magnetization ,Crystallography ,Molecular geometry ,Condensed matter physics ,Chemistry ,Antiferromagnetism ,Dielectric ,Crystal structure ,Néel temperature ,Powder diffraction ,Perovskite (structure) - Abstract
TlMO(3) perovskites (M(3+) = transition metals) are exceptional members of trivalent perovskite families because of the strong covalency of Tl(3+)-O bonds. Here we report on the synthesis, crystal structure and properties of TlCrO(3) investigated by Mössbauer spectroscopy, specific heat, dc/ac magnetization and dielectric measurements. TlCrO(3) perovskite is prepared under high pressure (6 GPa) and high temperature (1500 K) conditions. The crystal structure of TlCrO(3) is refined using synchrotron X-ray powder diffraction data: space group Pnma (no. 62), Z = 4 and lattice parameters a = 5.40318(1) Å, b = 7.64699(1) Å and c = 5.30196(1) Å at 293 K. No structural phase transitions are found between 5 and 300 K. TlCrO(3) crystallizes in the GdFeO(3)-type structure similar to other members of the perovskite chromite family, ACrO(3) (A(3+) = Sc, In, Y and La-Lu). The unit cell volume and Cr-O-Cr bond angles of TlCrO(3) are close to those of DyCrO(3); however, the Néel temperature of TlCrO(3) (TN≈ 89 K) is much smaller than that of DyCrO(3) and close to that of InCrO(3). Isothermal magnetization studies show that TlCrO(3) is a fully compensated antiferromagnet similar to ScCrO(3) and InCrO(3), but different from RCrO(3) (R(3+) = Y and La-Lu). Ac and dc magnetization measurements with a fine step of 0.2 K reveal the existence of two Néel temperatures with very close values at T(N2) = 87.0 K and T(N1) = 89.3 K. Magnetic anomalies near T(N2 )are suppressed by static magnetic fields and by 5% iron doping.
- Published
- 2015
39. Magneto-orbital ordering in the divalent A -site quadruple perovskite manganites AMn7O12 ( A=Sr , Cd, and Pb)
- Author
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Roger Johnson, Noriki Terada, Paolo G. Radaelli, Pascal Manuel, I. S. Glazkova, Dmitry D. Khalyavin, and Alexei A. Belik
- Subjects
Physics ,Ionic radius ,Magnetism ,Jahn–Teller effect ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,Coupling (probability) ,01 natural sciences ,Crystallography ,0103 physical sciences ,Phenomenological model ,Antiferromagnetism ,010306 general physics ,0210 nano-technology ,Ground state - Abstract
Through analysis of variable-temperature neutron powder-diffraction data, we present solutions for the magnetic structures of ${\mathrm{SrMn}}_{7}{\mathrm{O}}_{12}$, ${\mathrm{CdMn}}_{7}{\mathrm{O}}_{12}$, and ${\mathrm{PbMn}}_{7}{\mathrm{O}}_{12}$ in all long-range ordered phases. The three compounds were found to have magnetic structures analogous to that reported for ${\mathrm{CaMn}}_{7}{\mathrm{O}}_{12}$. They all feature a higher-temperature lock-in phase with commensurate magneto-orbital coupling and a delocked multi-k magnetic ground state where incommensurate magneto-orbital coupling gives rise to a constant-moment magnetic helix with modulated spin helicity. ${\mathrm{CdMn}}_{7}{\mathrm{O}}_{12}$ represents a special case in which the orbital modulation is commensurate with the crystal lattice and involves stacking of fully and partially polarized orbital states. Our results provide a robust confirmation of the phenomenological model for magneto-orbital coupling previously presented for ${\mathrm{CaMn}}_{7}{\mathrm{O}}_{12}$. Furthermore, we show that the model is universal to the ${A}^{2+}$ quadruple perovskite manganites synthesized to date and that it is tunable by selection of the $A$-site ionic radius.
- Published
- 2017
40. Antiferroelectric properties and site occupations of<tex>R^{3+}$</tex> cations in <tex>Ca_{8}MgR(PO_{4})_{7}$</tex> luminescent host materials
- Author
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Evgeniya S. Zhukovskaya, Dina V. Deyneko, Masahiko Tanaka, Alexei A. Belik, Joke Hadermann, Bogdan I. Lazoryak, O. V. Baryshnikova, A.E. Savon, Nikolay G. Dorbakov, Sergey Yu. Stefanovich, Yoshio Katsuya, and Vladimir A. Morozov
- Subjects
Phase transition ,Materials science ,Mechanical Engineering ,Physics ,Metals and Alloys ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Crystallography ,Chemistry ,Differential scanning calorimetry ,Electron diffraction ,Mechanics of Materials ,Materials Chemistry ,Antiferroelectricity ,Emission spectrum ,0210 nano-technology ,Luminescence ,Engineering sciences. Technology ,Powder diffraction - Abstract
Ca8MgR(PO4)(7) = La, Pr, Nd, Sm-Lu, and Y) phosphates with a beta-Ca-3(PO4)(2) related structure were prepared by a standard solid-state method in air. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements led to the conclusion that all Ca8MgR(PO4)(7) are centrosymmetric and go to another centrosymmetric phase in the course of a first-order antiferroelectric phase transition well above room temperature (RT). High-temperature electron diffraction showed that the symmetry changes from R (3) over barc to R (3) over barm during the phase transition. Structures of Ca8MgR(PO4)(7) at RT were refined by the Rietveld method in centrosymmetric space group R (3) over barc. Mg2+ cations occupy the M5 site; the occupancy of the M1 site by R3+ cations increases monotonically from 0.0389 for R = La to 0.1667 for R = Er-Lu, whereas the occupancy of the M3 site by R3+ cations decreases monotonically from 0.1278 for R = La to 0 for R = Er-Lu. In the case of R = Er-Lu, the M3 site is occupied only by Ca2+ cations. P1O(4) tetrahedra and cations at the M3 site are disordered in the R (3) over barc structure of Ca8MgEu(PO4)(7). Using synchrotron X-ray powder diffraction, we found that annealing conditions do not significantly affect the distribution of Ca2+ and Eu3+ cations between the structure positions of Ca8MgEu(PO4)(7). Luminescent properties of CasMgEu(PO4)(7) powder samples were investigated under near-ultraviolet (n-UV) light. Excitation spectra of CasMgEu(PO4)(7) show the strongest absorption at about 395 nm that matches with commercially available n-UV-emitting GaN-based LED chips. Emission spectra show an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+. (C) 2016 Elsevier B.V. All rights reserved.
- Published
- 2017
41. Perovskite-Structure TlMnO3: A New Manganite with New Properties
- Author
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Yana S. Glazkova, Alexey V. Sobolev, Wei Yi, Yu Kumagai, Alexei A. Belik, Akira Sato, Igor A. Presniakov, Yoshitaka Matsushita, and Nicola A. Spaldin
- Subjects
Inorganic Chemistry ,Magnetization ,Crystallography ,Condensed matter physics ,Electrical resistivity and conductivity ,Chemistry ,Mössbauer spectroscopy ,Thermal decomposition ,Antiferromagnetism ,Crystal structure ,Physical and Theoretical Chemistry ,Manganite ,Perovskite (structure) - Abstract
We synthesize a new member of the AMnO3 perovskite manganite family (where A is a trivalent cation)—thallium manganite, TlMnO3—under high-pressure (6 GPa) and high-temperature (1500 K) conditions and show that the structural and magnetic properties are distinct from those of all other AMnO3 manganites. The crystal structure of TlMnO3 is solved and refined using single-crystal X-ray diffraction data. We obtain a triclinically distorted structure with space group P1 (No. 2), Z = 4, and lattice parameters a = 5.4248(2) A, b = 7.9403(2) A, c = 5.28650(10) A, α = 87.8200(10)°, β = 86.9440(10)°, and γ = 89.3130(10)° at 293 K. There are four crystallographic Mn sites in TlMnO3 forming two groups based on the degree of their Jahn–Teller distortions. Physical properties of insulating TlMnO3 are investigated with Mossbauer spectroscopy and resistivity, specific heat, and magnetization measurements. The orbital ordering, which persists to the decomposition temperature of 820 K, suggests A-type antiferromagnetic ord...
- Published
- 2014
42. High-pressure synthesis, crystal structure and magnetic properties of Ba3CuOs2O9
- Author
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Hongbin Liang, Jie Chen, Yoshio Katsuya, Lirong Zheng, Yoshitaka Matsushita, Hai L. Feng, Alexei A. Belik, Man-Rong Li, Tsujimoto Yoshihiro, Kazunari Yamaura, and Masahiko Tanaka
- Subjects
Inorganic Chemistry ,Crystallography ,Materials science ,Structural Biology ,High pressure ,General Materials Science ,Crystal structure ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Biochemistry - Published
- 2019
43. Crystal structure and properties of high-pressure-synthesized BiRhO3, LuRhO3, and NdRhO3
- Author
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Qifeng Liang, Xiao Hu, Alexei A. Belik, Yoshitaka Matsushita, Masahiko Tanaka, and Wei Yi
- Subjects
Electron pair ,Materials science ,Inorganic chemistry ,Space group ,Crystal structure ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Paramagnetism ,Crystallography ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Orthorhombic crystal system ,Physical and Theoretical Chemistry ,Powder diffraction ,Perovskite (structure) - Abstract
GdFeO3-type orthorhombic perovskite compounds BiRhO3, LuRhO3, and NdRhO3 were prepared using a high-pressure and high-temperature technique at 6 GPa and 1300–1600 K. Their crystal structures were investigated using synchrotron X-ray powder diffraction data: a=5.8098(3) A, b=7.7720(4) A, and c=5.3510(3) A for BiRhO3; a=5.75519(1) A, b=7.77218(2) A, and c=5.37572(1) A for NdRhO3, and a=5.66981(1) A, b=7.51205(2) A, and c=5.18520(1) A for LuRhO3. BiRhO3 crystallizes in the centrosymmetric space group Pnma (No. 62) similar to LuRhO3 and NdRhO3 despite the presence of the lone electron pair of Bi3+ and the non-magnetic ground state of Rh3+. BiRhO3 and LuRhO3 are non-magnetic, and NdRhO3 shows paramagnetic behavior from Nd3+ ions. The specific heat of BiRhO3, LuRhO3, and NdRhO3 in different applied magnetic fields was also investigated. An energy gap of BiRhO3 was estimated to be about 1.3 eV from diffuse reflectance spectra and 0.95 eV from first-principle calculations with U=3.5 eV.
- Published
- 2013
44. Synthesis, structural and physical properties of ScMn2O4
- Author
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Zhen Chen, Yong Shi, H. X. Yang, Chunxin Ma, Alexei A. Belik, Hai-Jun Tian, L. Wang, and Yuanbin Qin
- Subjects
Phase transition ,Condensed matter physics ,Chemistry ,Jahn–Teller effect ,Spinel ,General Chemistry ,Crystal structure ,engineering.material ,Condensed Matter Physics ,Heat capacity ,Magnetic susceptibility ,Crystallography ,Octahedron ,Ferrimagnetism ,Materials Chemistry ,engineering - Abstract
A new inverse spinel ScMn2O4 has been synthesized and characterized by measurements of structural and physical properties. The crystal structure of ScMn2O4, similar with the spinel Mn3O4, is made up of Mn2+ located at tetrahedral site and Mn3+/Sc3+ ions randomly located at the octahedral site. Experimental results of magnetic susceptibility and heat capacity demonstrate that ScMn2O4 undergoes a ferrimagnetic phase transition at the temperature of about 58 K. Extensive analyses on the data obtained from structural refinement, electronic structural calculation and EELS spectra measurement suggests that substitution of Sc for Mn in MnO6 octahedron could greatly suppress Jahn-Teller distortions in comparison with what observed in Mn3O4. (C) 2012 Elsevier Ltd. All rights reserved.
- Published
- 2013
45. ChemInform Abstract: LiNbO3-Type Oxide (Tl1-xScx)ScO3: High-Pressure Synthesis, Crystal Structure, and Electronic Properties
- Author
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Yoshio Katsuya, Alexei A. Belik, Yu Kumagai, Masahiko Tanaka, Wei Yi, and Fumiyasu Oba
- Subjects
chemistry.chemical_compound ,Polarization density ,Chemistry ,Phase (matter) ,Oxide ,Analytical chemistry ,General Medicine ,Crystal structure ,Atmospheric temperature range ,Stoichiometry ,Powder diffraction ,Ambient pressure - Abstract
We investigate the synthesis of a thallium scandate, TlScO3, under high-pressure (6–7.7 GPa) and high-temperature (1373–1773 K) conditions. At 6 GPa, a LiNbO3-type phase appears in a narrow temperature range and in mixtures with other phases. At 7.7 GPa and 1673 K, a new LiNbO3-type oxide is found with a composition of (Tl1–xScx)ScO3 and x ≈ 0.26 as determined by structural analysis from X-ray powder diffraction data. It crystallizes in space group R3c (No. 161) with lattice parameters of a = 5.50283(7) A and c = 14.4606(2) A. It is stable at least up to 800 K at ambient pressure. The point-charge model gives an electric polarization of 60 μC/cm2. First-principles calculations show that centrosymmetric ilmenite-type and polar LiNbO3-type structures of stoichiometric TlScO3 have almost the same lowest energy, and the next stable structure is a GdFeO3-type perovskite structure.
- Published
- 2016
46. BiGaO3-Based Perovskites: A Large Family of Polar Materials
- Author
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Dmitriy A. Rusakov, Alexei A. Belik, Eiji Takayama-Muromachi, and Takao Furubayashi
- Subjects
Materials science ,General Chemical Engineering ,Inorganic chemistry ,General Chemistry ,Crystal structure ,Ion ,Crystallography ,Group (periodic table) ,Homogeneous space ,Materials Chemistry ,Multiferroics ,Isostructural ,Powder diffraction ,Solid solution - Abstract
Solid solutions of BiGaxM1–xO3 (M = Cr, Mn, and Fe) were prepared using the high-pressure high-temperature method at 6 GPa and 1700 K (M = Cr and Fe) and 1300 K (M = Mn). The formation of a large family of polar materials with R3c and Cm symmetries was found. Crystal structures were studied with laboratory X-ray powder diffraction: space group Cm, a = 5.3150(1) A, b = 5.2960(1) A, c = 4.6965(1) A, and β = 92.556(2)° for BiGa0.4Fe0.6O3; space group Cm, a = 5.2798(1) A, b = 5.2577(1) A, c = 4.6465(1) A, and β = 91.974(2)° for BiGa0.7Mn0.3O3; space group R3c, a = 5.51623(8) A and c = 13.61391(17) A for BiGa0.4Cr0.6O3. Samples with the Cm symmetry have square-pyramidal coordination of (Ga,M)3+ ions, and their structure is very similar with the structure of supertetragonal PbVO3, BiCoO3, and Bi2ZnTiO6 materials. Samples with the R3c symmetry are isostructural with BiFeO3 and have comparable calculated (based on the point-charge model) spontaneous polarization (58 μC/cm2 for BiGa0.4Cr0.6O3). The calculated pola...
- Published
- 2012
47. Crystal Structures and Properties of Perovskites ScCrO3 and InCrO3 with Small Ions at the A Site
- Author
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Masahiko Tanaka, Yoshitaka Matsushita, Alexei A. Belik, and Eiji Takayama-Muromachi
- Subjects
Materials science ,General Chemical Engineering ,Inorganic chemistry ,General Chemistry ,Crystal structure ,Dielectric ,Ion ,Crystallography ,Magnetization ,Ferromagnetism ,Materials Chemistry ,Antiferromagnetism ,Multiferroics ,Powder diffraction - Abstract
ScCrO3 and InCrO3 were synthesized at high pressure of 6 GPa and 1500 K. Crystal structures of ScCrO3 and InCrO3 were studied with synchrotron X-ray powder diffraction. They crystallize in the GdFeO3-type perovskite structure (space group Pnma, a = 5.35845(1) A, b = 7.37523(1) A, c = 5.03139(1) A for ScCrO3 and a = 5.35536(1) A, b = 7.54439(1) A, c = 5.16951(1) A for InCrO3). The physical properties of ScCrO3 and InCrO3 were investigated with specific heat, ac/dc magnetization, and dielectric measurements and compared with those of YCrO3 with nonmagnetic Y3+ ions at the A site. Antiferromagnetic transitions occur at TN = 73 K in ScCrO3 and 93 K in InCrO3 in agreement with the general trend of ACrO3 (A = Y and rare earths) where TN decreases with decreasing the radius of the A ions. Extremely weak ferromagnetism was found in ScCrO3 and InCrO3 in contrast to YCrO3. Ac magnetization measurements revealed some peculiarities in behavior of ScCrO3 and InCrO3, namely, double-peak anomalies just below TN. Dielect...
- Published
- 2012
48. ChemInform Abstract: High-Pressure Synthesis, Crystal Structures, and Properties of CdMn7O12and SrMn7O12Perovskites
- Author
-
Noriki Terada, Igor A. Presniakov, Yoshio Katsuya, Masahiko Tanaka, Alexey V. Sobolev, Alexei A. Belik, Yana S. Glazkova, and Yoshitaka Matsushita
- Subjects
Chemical engineering ,Chemistry ,High pressure ,Inorganic chemistry ,General Medicine ,Crystal structure ,Hot pressing ,Stoichiometry - Abstract
CdMn7O12 (I) and SrMn7-xFexO12 (x = 0 (II), 0.08, 0.5) perovskites are prepared by hot pressing of stoichiometric mixtures of Mn2O3, MnO2, and CdO as well as Mn2O3, Fe2O3, and 4H-SrMnO3, resp.
- Published
- 2015
49. Low-temperature structural phase transition in synthetic libethenite Cu2PO4OH
- Author
-
Alexei A. Belik, Shunsuke Tsuda, Panče Naumov, and Jungeun Kim
- Subjects
Phase transition ,Materials science ,Order (ring theory) ,Crystal structure ,Atmospheric temperature range ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,Phase (matter) ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,Single crystal ,Powder diffraction ,Monoclinic crystal system - Abstract
Low-temperature structural properties of the synthetic mineral libethenite Cu{sub 2}PO{sub 4}OH were investigated by single-crystal X-ray diffraction, synchrotron X-ray powder diffraction, specific heat measurements, and Raman spectroscopy. A second-order structural phase transition from the Pnnm symmetry (a=8.0553(8) A, b=8.3750(9) A, c=5.8818(6) A at 180 K) to the P2{sub 1}/n symmetry (a=8.0545(8) A, b=8.3622(9) A, c=5.8755(6) A, {beta}=90.0012(15) at 120 K) was found at 160 K during cooling. At 120 K, the monoclinic angle is 90.0012(15) from single crystal X-ray data vs 90.083(1) from powder X-ray diffraction data. The P2{sub 1}/n-to-Pnnm transition may be a general feature of the adamite-type compounds, M{sub 2}XO{sub 4}OH. - Graphical Abstract: Fragments of experimental synchrotron X-ray powder diffraction patterns of Cu{sub 2}PO{sub 4}OH between 100 and 280 K. Arrows show additional reflections that appear below 160 K in the monoclinic P2{sub 1}/n phase. Highlights: > A low-temperature phase transition was found in the mineral libethenite Cu{sub 2}PO{sub 4}OH. > No magnetic anomalies and weak specific heat anomalies are detected. > Phase transition is of the second order. > Libethenite may exemplify a general feature of the adamite-type compounds.
- Published
- 2011
50. Perovskite, LiNbO3, Corundum, and Hexagonal Polymorphs of (In1–xMx)MO3
- Author
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Takao Furubayashi, Eiji Takayama-Muromachi, Hitoshi Yusa, and Alexei A. Belik
- Subjects
Chemistry ,Inorganic chemistry ,Corundum ,General Chemistry ,Crystal structure ,engineering.material ,Biochemistry ,Catalysis ,Crystallography ,Colloid and Surface Chemistry ,Differential thermal analysis ,Mössbauer spectroscopy ,engineering ,Antiferromagnetism ,Powder diffraction ,Perovskite (structure) ,Ambient pressure - Abstract
LiNbO(3) (LN), corundum (cor), and hexagonal (hex) phases of (In(1-x)M(x))MO(3) (x = 0.143; M = Fe(0.5)Mn(0.5)) were prepared. Their crystal structures were investigated with synchrotron X-ray powder diffraction, and their properties were studied by differential thermal analysis, magnetic measurements, and Mössbauer spectroscopy. The LN-phase was prepared at high pressure of 6 GPa and 1770 K; it crystallizes in space group R3c with a = 5.25054(7) Å, c = 13.96084(17) Å, and has a long-range antiferromagnetic ordering near T(N) = 270 K. The cor- and hex-phases were obtained at ambient pressure by heating the LN-phase in air up to 870 and 1220 K, respectively. The cor-phase crystallizes in space group R-3c with a = 5.25047(10) Å, c = 14.0750(2) Å, and the hex-phase in space group P6(3)/mmc with a = 3.34340(18) Å, c = 11.8734(5) Å. T(N) of the cor-phase is about 200 K, and T(N) of the hex-phase is about 140 K. During irreversible transformations of LN-(In(1-x)M(x))MO(3) with the (partial) cation ordering, the In(3+), Mn(3+), and Fe(3+) cations become completely disordered in one crystallographic site of the corundum structure, and then they are (partially) ordered again in the hex-phase. LN-(In(1-x)M(x))MO(3) exhibits a reversible transformation to a perovskite GdFeO(3)-type structure (space group Pnma; a = 5.2946(3) Å, b = 7.5339(4) Å, c = 5.0739(2) Å at 10.3 GPa) at room temperature and pressure of about 5 GPa.
- Published
- 2011
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