Search

The RTX (where R represents rare earth, T represents 3d/4d/5d transition metal, and X represents p-block element) series comprises an extensive collection of equiatomic (1:1:1) intermetallic compounds that exhibit diverse crystal and magnetic structures with their vast array of physical properties, which includes field-induced phase transitions, commensurate, incommensurate, superconductivity, non-trivial topology, etc. In the present work, the exchange interactions and phonon topology of EuAuAs, GdAuGe, and GdAgGe have been discussed. By correlating the spin configurations to the underlying Heisenberg spin model, we have successfully estimated the exchange interactions. Furthermore, by using the mean-field approximation, the Neel temperatures of rare-earth compounds have been reported, which is consistent with the experimental value. The phonon dispersion of EuAuAs and GdAuGe exhibits non-trivial topological phononic states with nodal surfaces and Dirac points on the k z = π plane. The calculated phonon spectrum of GdAgGe reveals the presence of a nodal line along the k z = π plane. The exploration of phonon topology opens up a new pathway toward comprehending and harnessing the exotic physical characteristics exhibited by these rare-earth compounds and other analogous quantum materials. [ABSTRACT FROM AUTHOR]

The rich and unique energy level structure arising from 4fn inner shell configuration of trivalent lanthanide ions (Ln3+) renders them highly attractive for light‐emitting applications. Currently, research primarily focuses on Ln3+ doping in either traditional garnets or the recently developed perovskite phosphors. However, there have been few reports on stable phosphors crystallized with pure lanthanide elements. Herein, a universal solution‐based route to eight Ln3+‐based metal halides from the organic‐inorganic A4LnX7 family is described, where A+ = 4,4‐difluoropiperidinium (DFPD+), Ln3+ = Nd3+, Eu3+, Ho3+, Sm3+, Tm3+, Tb3+, Yb3+, Er3+, and X− = Cl−, Br−. Visible photoluminescence (PL) is observed from Tb3+‐, Eu3+‐, Ho3+‐, and Sm3+‐based compounds with Tb and Eu compositions exhibiting high PL quantum yields of 90–100%; Nd3+‐, Tm3+‐, Yb3+‐, and Er3+‐based crystals show fascinating near‐infrared emission. Light‐emitting diodes (LEDs) fabricated with (DFPD)4TbCl7 yield characteristic emission of Tb3+, representing the first demonstration of electroluminescence from these organic‐inorganic Ln3+‐based metal halides. Moreover, these materials exhibit distinct excitation wavelength‐dependent emission after alloying with different Ln3+ ions, making them interesting for multicolor display and multilevel information encryption applications. It is foreseen that this study will open up the way to a possible design of robust optoelectronic devices based on lanthanide metal halides. [ABSTRACT FROM AUTHOR]

The achievement of significant photoluminescence (PL) in lanthanide ions (Ln3+) has primarily relied on host sensitization, where energy is transferred from the excited host material to the Ln3+ ions. However, this luminous mechanism involves only one optical antenna, namely the host material, which limits the accessibility of excitation wavelength‐dependent (Ex‐De) PL. Consequently, the wider application of Ln3+ ions in light‐emitting devices is hindered. In this study, we present an organic–inorganic compound, (DMA)4LnCl7 (DMA+=[CH3NH2CH3]+, Ln3+=Ce3+, Tb3+), which serves as an independent host lattice material for efficient Ex‐De emission by doping it with trivalent antimony (Sb3+). The pristine (DMA)4LnCl7 compounds exhibit high luminescence, maintaining the characteristic sharp emission bands of Ln3+ and demonstrating a high PL quantum yield of 90–100 %. Upon Sb3+ doping, the compound exhibits noticeable Ex‐De emission with switchable colors. Through a detailed spectral study, we observe that the prominent energy transfer process observed in traditional host‐sensitized systems is absent in these materials. Instead, they exhibit two independent emission centers from Ln3+ and Sb3+, each displaying distinct features in luminous color and radiative lifetime. These findings open up new possibilities for designing Ex‐De emitters based on Ln3+ ions. [ABSTRACT FROM AUTHOR]

We study the atomic and electronic structures of the monolayer Kondo lattice CePt2/Pt(111) using scanning tunneling microscopy/spectroscopy (STM/STS). A monolayer (2×2)-CePt2 is formed by depositing Ce atoms on Pt(111) and annealing at 720 K. Atomically resolved STM images reveal that the monolayer (2×2)-CePt2 is protected by a chemically inert topmost Pt4 layer. The quasiparticle interference (QPI) measured on the (2×2) structure indicates a Shockley-type surface state similar to that on Pt(111) with a downward shift due to charge transfer from the underneath CePt2 layer. We discuss a possible two-dimensional coherent Kondo effect (heavy fermion) with the observed STS spectra. [ABSTRACT FROM AUTHOR]

The structural parameters of the rare-earth diacetate halide trihydrates, RE(OAc)2Hal·3H2O with RE = Ce − (Pm) − Lu and Hal = Cl, Br, have been determined by low temperature, high-resolution SCXRD in order to examine the effect of lanthanide contraction on the coordination geometry in this series of isomorphous compounds consisting of cationic, acetate-bridged, non-linear, one-dimensional coordination polymers of composition [RE(H2O)3(OAc)2]+ and laterally hydrogen bonded halide ions, Hal−. Although the shrinkage of the unit cell volume follows lanthanide contraction very well over the complete range of investigated RE elements, many other parameters (i.e., lattice constants, angles and distances in the RE··· RE alignment, RE-O bond lengths, etc.) exhibit a more complex response on lanthanide contraction often expressed by sigmoid curves that can be ascribed to a continuous transition from CN9 (RE = Ce) to CN8 (RE = Lu) as one acetate group loses the chelate function, an effect accompanied by significant structural changes of the carboxylate group. Therefore, data are best analyzed by use of two subsets represented by the two different structure types of Ce and Lu, the structural features of which change with decreasing/increasing the size of RE3+, up to the borderline between both subsets. [ABSTRACT FROM AUTHOR]

The structure family of the rare‐earth calcium oxoborates RX2Z2$RX_{2}{Z}_{2}$O[BO3]3 (RCOB) has been investigated mainly with regard to their optical characteristics. Due to their monoclinic‐domatic structure they exhibit pyro‐ and piezoelectric properties, which is not dependent on the numerous possible substitutions of the rare‐earth cation site R. The rare‐earth cations are known to show partial disorder with the earth alkaline cation positions X and Z. To study whether a stabilization of the cation occupation is possible without disorder, calcium oxoborates are chemically modified using the Ca substitutes, Sr, Na, Y, Gd on the X and Z positions. No oxoborate phases can be synthesized by coupled substitution of Ca with Sr, Na, and a rare‐earth element. Only with single substitution of Sr the oxoborate phases can be synthesized. It is found that up to 35% Sr can be incorporated into the structure. From the synthesized Gd(Ca4−x$_{4-{{x}}}$Srx)O[BO3]3 precursor material, single crystals have been grown and used for the refinement of the first structure model. The structures have been refined in space group C1m1$C1m1$. A replacing only of Ca with Sr, mainly on the X position, has been observed. The stoichiometry resulting from the refinement is Gd(Ca3.319Sr0.681)O[BO3]3 and Gd(Ca2.592Sr1.408)O[BO3]3. [ABSTRACT FROM AUTHOR]

The structure family of the rare‐earth calcium oxoborates RX2Z2$RX_{2}{Z}_{2}$O[BO3]3 (RCOB) has been investigated mainly with regard to their optical characteristics. Due to their monoclinic‐domatic structure they exhibit pyro‐ and piezoelectric properties, which is not dependent on the numerous possible substitutions of the rare‐earth cation site R. The rare‐earth cations are known to show partial disorder with the earth alkaline cation positions X and Z. To study whether a stabilization of the cation occupation is possible without disorder, calcium oxoborates are chemically modified using the Ca substitutes, Sr, Na, Y, Gd on the X and Z positions. No oxoborate phases can be synthesized by coupled substitution of Ca with Sr, Na, and a rare‐earth element. Only with single substitution of Sr the oxoborate phases can be synthesized. It is found that up to 35% Sr can be incorporated into the structure. From the synthesized Gd(Ca4−x$_{4-{{x}}}$Srx)O[BO3]3 precursor material, single crystals have been grown and used for the refinement of the first structure model. The structures have been refined in space group C1m1$C1m1$. A replacing only of Ca with Sr, mainly on the X position, has been observed. The stoichiometry resulting from the refinement is Gd(Ca3.319Sr0.681)O[BO3]3 and Gd(Ca2.592Sr1.408)O[BO3]3. [ABSTRACT FROM AUTHOR]

Herein we reported the crystal structure and crystal chemistry of orthorhombic perovskite type Nd2CuTiO6 in between 2 K and 290 K as observed from the in situ temperature-dependent powder neutron diffraction (PND) studies. It is observed that the cations in octahedral sites are statistically occupied, and the ambient temperature orthorhombic structure is retained throughout the temperature range of the study. Absence of any long-range magnetic ordering down to 2 K is confirmed by both low-temperature PND and magnetization studies. The lattice shows strong anisotropic thermal expansion with increasing temperature, viz. almost no or feeble negative expansion along the a-axis while appreciably larger expansion along the other two axes (αb = 10.6 × 10−6 K−1 and αc = 9.8 × 10−6 K−1). A systematic change in the rotation of octahedral units with temperature was observed in the studied temperature range, while the expansion of unit cells is predominantly associated with the polyhedral units around the Nd3Ions. The temperature-dependent relative change in unit cell parameters as well as coefficients of axial thermal expansion show anomalous behavior at lower temperatures, and that seems to be related to the electronic contributions to lattice expansion. [ABSTRACT FROM AUTHOR]

Experimental results on the bis[(μ2-etoxi)(benzoyl trifluoroacetonato)(nitrato)(1,10-phenantroline)europium(III)]1,10-phenantroline europium(III) coordination complex (hereafter, [Eu(μ2-OC2H5)(btfa)(NO3)(phen)]2·phen) are described. The complex is characterized by photoluminescence (PL) and infrared spectroscopy. Photoluminescence spectra of the complex exhibit strong emission with specific narrow emission bands associated with the 5D0→7Fj (j = 0–4) transitions. The pattern of emission band splitting and the luminescence time decay suggest the presence of at least two different sites of the Eu3+ ion in a low-symmetry environment. The absolute PL quantum yield of the complex is determined to be 49.2%.Sunt prezentate rezultate experimentale pentru complexul coordinativ al europiului III) - [Eu(μ2-OC2H5)(btfa)(NO3)(phen)]2phen. Complexul a fost caracterizat prin spectroscopia de fotoluminescență și spectroscopia în infraroșu. Spectrele de fotoluminescență ale complexului reprezintă benzi de emisie puternice asociate cu tranzițiile 5D0→7Fj (j=0-4). Caracterul despicării benzilor de emisie, cât şi timpul de relaxare al luminescenței indică prezența a cel puțin două site-uri diferite ale ionului Eu3+ în mediu cu simetrie redusă. A fost determinat randamentul cuantic absolut al complexului de 49,2%.

The structural parameters of the rare-earth diacetate halide trihydrates, RE(OAc)2Hal·3H2O with RE = Ce − (Pm) − Lu and Hal = Cl, Br, have been determined by low temperature, high-resolution SCXRD in order to examine the effect of lanthanide contraction on the coordination geometry in this series of isomorphous compounds consisting of cationic, acetate-bridged, non-linear, one-dimensional coordination polymers of composition [RE(H2O)3(OAc)2]+ and laterally hydrogen bonded halide ions, Hal−. Although the shrinkage of the unit cell volume follows lanthanide contraction very well over the complete range of investigated RE elements, many other parameters (i.e., lattice constants, angles and distances in the RE··· RE alignment, RE-O bond lengths, etc.) exhibit a more complex response on lanthanide contraction often expressed by sigmoid curves that can be ascribed to a continuous transition from CN9 (RE = Ce) to CN8 (RE = Lu) as one acetate group loses the chelate function, an effect accompanied by significant structural changes of the carboxylate group. Therefore, data are best analyzed by use of two subsets represented by the two different structure types of Ce and Lu, the structural features of which change with decreasing/increasing the size of RE3+, up to the borderline between both subsets.

The rare-earth palladium silicides host an array of complex magnetic phases. In this paper, we report the growth of large single crystals of the R 2 PdSi 3 family, (where R = Ce, Nd, Gd, Tb, Ho and Er) by the floating zone technique using a high-power xenon arc-lamp furnace. The crystal boules obtained have been examined for their quality using x-ray diffraction techniques, elemental analysis, and their magnetic properties have been investigated through temperature dependent magnetisation measurements. • Crystal growth of R 2 PdSi 3 (where R = Ce, Nd, Gd, Tb, Ho and Er) compounds. • Crystal growth of R 2 PdSi 3 by the optical floating zone technique. • Growth parameters including growth rate, rotation rate and growth atmosphere. • Characterised by powder x-ray, Laue x-ray diffraction and compositional analysis. • Magnetisation susceptibility measurements of all compounds. [ABSTRACT FROM AUTHOR]

We report, for the first time to our knowledge, on the polymer nanocomposite sunlight spectrum down-converters made by the concurrent multi-beam multi-target pulsed laser deposition (CMBMT-PLD) of phosphor and polymer in ambient air. Phosphor PLD targets were made of down-converting rare-earth (RE)-doped fluorides NaYF4:Yb3+,Er3+, and NaYF4:Yb3+,Tm3+ with a Stokes shift of 620 nm (from 360 to 980 nm), minimizing the effect of re-absorption. The phosphors were synthesized by the wet method. Polymer target was made of poly (methyl methacrylate) known as PMMA. Target ablation was conducted with 1,064 nm beams from an Nd:YAG Q-switched laser. Beam intensity was 2.8 × 1016 W/cm2 for both targets. The substrate was a microscope glass slide. Phosphor nanoparticles with a size ranging from 10 to 50 nm were evenly distributed in the polymer matrix during deposition. The nanoparticles retained the crystalline structure and the fluorescent properties of the phosphor target. There was no noticeable chemical decomposition of the deposited polymer. The products of laser-induced reaction of the polymer target with atmospheric gases did not reach the substrate during PLD. Post-heating of the substrate at ∼90°C led to fusion of separate polymer droplets into uniform coating. Quantum yield of the down-conversion polymer nanocomposite film was estimated to be not less than ∼5%. The proposed deposition method can find its application in making commercial-size down-converter coatings for photo-voltaic solar power applications.

Herein we reported the crystal structure and crystal chemistry of orthorhombic perovskite type Nd2CuTiO6 in between 2 K and 290 K as observed from the in situ temperature-dependent powder neutron diffraction (PND) studies. It is observed that the cations in octahedral sites are statistically occupied, and the ambient temperature orthorhombic structure is retained throughout the temperature range of the study. Absence of any long-range magnetic ordering down to 2 K is confirmed by both low-temperature PND and magnetization studies. The lattice shows strong anisotropic thermal expansion with increasing temperature, viz. almost no or feeble negative expansion along the a-axis while appreciably larger expansion along the other two axes (αb = 10.6 × 10−6 K−1 and αc = 9.8 × 10−6 K−1). A systematic change in the rotation of octahedral units with temperature was observed in the studied temperature range, while the expansion of unit cells is predominantly associated with the polyhedral units around the Nd3Ions. The temperature-dependent relative change in unit cell parameters as well as coefficients of axial thermal expansion show anomalous behavior at lower temperatures, and that seems to be related to the electronic contributions to lattice expansion.

The polycrystalline Yb 23 Cu 7 Mg 4 -type {Gd, Tb} 23 Ni 7 In 4 compounds (space group P 6 3 / mmc , N 194, hP 68) were prepared by arc melting with following annealing. They exhibit ferromagnetic ordering below Curie temperature T C = 142 K for Gd 23 Ni 7 In 4 and T C = 112 K for Tb 23 Ni 7 In 4 , respectively. A field-sensitive antiferromagnetic transformation takes place around 90 K in Gd 23 Ni 7 In 4 and 106 K in Tb 26 Ni 7 In 4 , respectively. Down to 10 K, they are soft ferromagnets with magnetizations of 4.7 μ B /Gd for Gd 23 Ni 7 In 4 and 5.7 μ B /Tb for Tb 23 Ni 7 In 4 in 90 kOe. In a field change of 50 kOe around T C , Gd 23 Ni 7 In 4 shows magnetic entropy change of −4.7 J/kg⋅K at 133–143 K, while Tb 23 Ni 7 In 4 shows magnetic entropy change of −5.4 J/kg⋅K at 109 K. The magnetic ordering and magnetocaloric effects of arc-melted polycrystalline Yb 23 Cu 7 Mg 4 -type {Gd, Tb} 23 Ni 7 In 4 compounds (space group P 6 3 / mmc , N 194, hP 68) have been investigated using magnetic measurements in fields up to 90 kOe. They exhibit ferromagnetic ordering below Curie temperature T C = 142 K for Gd 23 Ni 7 In 4 and T C = 112 K for Tb 23 Ni 7 In 4 , respectively. A field-sensitive antiferromagnetic transformation takes place around 90 K in Gd 23 Ni 7 In 4 and 106 K in Tb 26 Ni 7 In 4 , respectively. Down to 10 K, they are soft ferromagnets with magnetizations of 4.7 μ B /Gd for Gd 23 Ni 7 In 4 and 5.7 μ B /Tb for Tb 23 Ni 7 In 4 in 90 kOe. In a field change of 50 kOe around T C , Gd 23 Ni 7 In 4 shows magnetic entropy change of −4.7 J/kg⋅K at 133–143 K, while Tb 23 Ni 7 In 4 shows magnetic entropy change of −5.4 J/kg⋅K at 109 K. [Display omitted] • Yb 23 Cu 7 Mg 4 -type Gd 23 Ni 7 In 4 and Tb 23 Ni 7 In 4 prepared via arc-furnace melting/annealing. • Gd 23 Ni 7 In 4 shows ferromagnetic ordering at 142 K and Tb 23 Ni 7 In 4 at 112 K. • They exhibit field sensitive LT antiferromagnetic-like transformation of magnetic ordering. • Down to 10 K, these compounds are soft non-collinear ferromagnets in fields up to 90 kOe. • Gd 23 Ni 7 In 4 has magnetic entropy change of −4.7 J/kg⋅K around T C (field change 0-50 kOe). • Tb 23 Ni 7 In 4 shows magnetic entropy change of −5.4 J/kg⋅K at T C (field change 0-50 kOe). [ABSTRACT FROM AUTHOR]

[Display omitted] • A robust Er 2 O 3 /UiO-66-NH 2 core–shell nanohybrid was fabricated. • In-situ assembling strategy induced the formation of coupled intermediate layer. • Cascade band structure and interfacial built-in electric field were constructed. • Directional transport and spatial separation of carriers promoted photoreduction. • The activity was triggered by readily CO 2 activation and fast charge-transfer. Interfacial charge transfer in nanocomposites is one of the leading factors to CO 2 photoreduction activity and selectivity; however, the modulation of interfacial contact still remains a compelling challenge. Here we present an in-situ assembly strategy to synthesize core–shell structured Er-UiO-66-NH 2 heterojunction photocatalysts, achieving a stable CO evolution rate of 106.2 μmol·g−1·h−1 and a selectivity over 92 %. Our findings demonstrate that the coupled intermediate layer formed by solvothermal transformation creates a charge-transfer channel between Er 2 O 3 and UiO-66-NH 2 , contributing to the effective spatial separation of photogenerated carriers. The well-defined gradient of band structures and interfacial built-in electric field at p-n heterojunctions direct photoelectrons migration, and facilitates the fast access to active Zr-oxo sites for efficient CO 2 reduction. In-situ DRIFTS unravels that the superior catalytic activities can be attributed to the strong adsorption and activation capabilities for CO 2 conversion to COOH* and CO* species. This work highlights an interfacial assembling strategy to design heterojunction photocatalysts for efficient solar fuel production. [ABSTRACT FROM AUTHOR]

To boost the performance for various applications, a rational bottom‐up design on materials is necessary. The defect engineering on nanoparticle at the atomic level can efficiently tune the electronic behavior, which offers great opportunities in enhancing the catalytic performance. In this paper, we optimized the surface oxygen vacancy concentration and created the lattice distortion in rare‐earth‐based perovskite oxide through gradient replacement of the B site with valence alternated element. The dual defects make the electron spin state transit from low spin state to high spin state, thus decreasing the charge transport resistance. Furthermore, assembly the modified nanoparticle subunits into the micro‐sized hollow multishelled structures can provide porous shells, abundant interior space and effective contact, which enables an enhanced mass transfer and a shorter charge transport path. As a result, the systemic design in the electronic and nano‐micro structures for catalyst has brought an excellent oxygen evolution performance. [ABSTRACT FROM AUTHOR]

The structural, electronic and luminescent properties of the tetragonal phase of Y2WO6 phosphors doped with different amounts of Eu3+ have been studied. All samples were synthesized via solid‐state methods, using NaCl as mineralizer. Through Rietveld refinement was found that the Eu3+ cations only occupy the Y1 (2c) sites of the host‐matrix. The thermal stability of the undoped sample was investigated using simultaneous TG‐DSC thermal analyses. The SEM analysis revealed that the doped and the undoped samples have tendency to form microcrystals with smooth surfaces and in both cases it is possible to observe some agglomerates of nanoparticles. Periodic Density Functional Theory calculations (DFT) were carried out to investigate the electronic properties of the undoped material; these results show good agreement with the experimental ones. The emission spectra of all doped‐samples are dominated by the electric dipole transition (ED) 5D0 → 7F2 located at 613 nm, which indicates that the Eu3+ ions are located in non‐centrosimetric sites in the host‐structure. [ABSTRACT FROM AUTHOR]

The heavy rare-earth-based Laves phases are well-studied intermetallic materials that stand out for their remarkably high magnetocaloric effects, particularly at cryogenic temperatures. In this study, we present the findings of our comprehensive investigation of cobalt Laves phases R Co 2 with R standing for erbium, holmium, dysprosium, and terbium. This includes the determination of the magnetocaloric effect by indirect methods using calorimetric and magnetization data. Furthermore, for the first time in these materials, we directly measured the adiabatic temperature change at high magnetic fields up to 20 T. The largest Δ T ad value of 17 K, we obtained for ErCo 2. Because the order of the transition significantly impacts the efficiency of thermodynamic cycles, we have also focused on determining the transition order in these materials. This was done through the application of established methods and a recently proposed quantitative criterion including the value of the local exponent n. Further, we compare our results with other materials using a straightforward material-based figure of merit - the temperature-averaged entropy change (TEC). Our results demonstrate the great potential of these materials for applications such as for magnetic hydrogen liquefaction. • A comprehensive experimental study was conducted on the magnetocaloric effect in Laves phases RCo2 (R=Er, Ho, Dy, Tb). • Directly obtained adiabatic temperature changes in RCo2 at high magnetic fields up to 20 T are provided for the first time. • Calorimetric, magnetization, and directly obtained data are in good agreement between each other. • The study highlights the potential of these materials in applications such as magnetic hydrogen liquefaction. [ABSTRACT FROM AUTHOR]

Starting from band structure calculations and 4f–5d–3d exchange interaction model, the magnetic properties of RCo 2 , RCo 3 , RCo 5 and both rhombohedral and hexagonal R 2 Co 1 7 series are analyzed. The complex and interdependent exchange interactions, within the spatial extent of the unit cell, are mediated by the R5d band polarizations, M 5 d . The Curie temperatures of the analyzed series show linear dependences, with the same rate for both light and heavy rare-earth compounds, when plotting as function of M 5 d values. The effects of substitutions at R and Co sites are discussed in correlation with changes in R5d band polarizations. [ABSTRACT FROM AUTHOR]

Treatment of β‐diketiminate ligands bearing different N‐aryl monoatomic substituents [HLH = (C6H5)N = C(Me)CH=C(Me)NH(C6H5), HLF = (2,6‐F2C6H3)N=C(Me)CH=C(Me)NH(2,6‐F2C6H3), and HLCl = (2,6‐Cl2C6H3)N=C(Me)CH=C(Me)NH(2,6‐Cl2C6H3)] with Ln(CH2SiMe3)3(THF)2 (Ln = Y and Lu) afforded a variety of β‐diketiminato rare‐earth metal complexes depending on substituents, namely, phenyl ring C–H bond activated complexes (L')(LH)Lu(THF) (1b, L' = (C6H4)N = C(Me)CH=C(Me)N(C6H5)), six‐coordinate homoleptic complexes (LH)3Ln [Ln = Y (1aa), Lu (1bb)], five‐coordinate monoalkyl complexes (LF)2Ln(CH2SiMe3) [Ln = Y (2a), Lu (2b)], and four‐coordinate dialkyl complexes (LCl)Ln(CH2SiMe3)2 [Ln = Y (3a), Lu (3b)]. All these complexes were characterized with NMR spectroscopy, and lutetium complexes 1b, 1bb and 3b were structurally validated by single‐crystal X‐ray diffraction analysis. Moreover, dialkyl complexes 3 promoted the polymerization of 2‐vinylpyridine (2‐VP) to produce atactic poly(2‐vinylpyridine) (P2VP) with quantitative yield. On activation with an equimolar amount of [Ph3C][B(C6F5)4], complexes 3 afforded highly isotactic P2VP with an mm value up to 94 %. Both 1H NMR spectrum and MALDI‐TOF mass analysis of an oligomer indicate that the polymerization was initiated by coordination insertion of 2‐VP into the Y‐CH2SiMe3 bond. [ABSTRACT FROM AUTHOR]

The crystal structures of the Gd8Ag19.5(2)Al45.2(2) (Gd4(Ag0.294Al0.706)32Ag0.340) and Ho8Ag21.2(2)Al43.3(2) (Ho4(Ag0.323Al0.677)32Ag0.252) compounds, which adopt the Yb8Cu17Al49-type structure with the space group I4/mmm, have been investigated by means of the X-ray powder diffraction. The structures of the compounds are characterized by the silver/aluminum mixing on several atomic positions and the partial occupancy of silver atoms on one atomic position. dc and ac magnetic data indicate antiferromagnetic properties below 46.5 K for Gd8Ag19.5Al45.2 and 15 K for Ho8Ag21.2Al43.3. In case of RE = Gd an anomaly observed in its magnetic susceptibility at 3.5 K suggests a magnetic transition of the order-order type. A metamagnetic phase transition is detected for RE = Ho. [ABSTRACT FROM AUTHOR]

The composites were obtained by the argon-arc cladding (AAC) of the Deloro22-Si3N4-Fe pre-placed powders on a TA1 titanium alloy substrate, which improved the wear resistance of the substrate. Such composites were investigated by means of the scanning electron microscope (SEM), the microscope and the high resolution transmission electron microscope (HRTEM). The results indicated that the amorphous phases were produced in such AAC composites, increasing the wear resistance. With addition of Y2O3, lots of the micro/nanoscale particles were formed, which further improved the wear resistance of such AAC composites. [ABSTRACT FROM AUTHOR]

The magnetic ordering of polycrystalline Mo 2 NiB 2 -type Tb 2 Co 2 Ga and Tb 2 Co 2 Al-based Sm 2-x Tb x Co 2 Al, Tb 2 Co 2 Al 1-x Ga x and Tb 2 Co 1.8 {Ni, Cu} 0.2 Al solid solutions has been established using bulk magnetic measurements. These compounds undergo a high-temperature ferromagnetic ordering and field sensitive transformation of magnetic ordering at low temperatures. The high-temperature ferromagnetic ordering is followed via negative magnetic entropy change and soft magnet properties, whereas low-temperature transformation of magnetic ordering indicates positive magnetic entropy change and excellent permanent magnet properties. The magnetic ordering of polycrystalline Mo 2 NiB 2 -type Tb 2 Co 2 Ga and Tb 2 Co 2 Al-based Sm 2-x Tb x Co 2 Al, Tb 2 Co 2 Al 1-x Ga x and Tb 2 Co 1.8 {Ni, Cu} 0.2 Al solid solutions has been established using bulk magnetic measurements. These compounds undergo a high-temperature ferromagnetic ordering and field sensitive transformation of magnetic ordering at low temperatures. The high-temperature ferromagnetic ordering is followed via negative magnetic entropy change and soft magnet properties, whereas low-temperature transformation of magnetic ordering indicates positive magnetic entropy change and excellent permanent magnet properties. Image 1 • Tb 2 Co 2 Ga and Tb 2 Co 2 Al-based solutions show high-temperature ferromagnetic ordering. • This HT ferromagnetic ordering corresponds to the negative ΔS m and soft magnet properties. • They exhibits low-temperature field sensitive transformation of magnetic ordering. • This LT transformation is followed positive ΔS m and permanent magnet properties. • Tb 2 Co 2 Ga is giant permanent magnet with H coer of 48 kOe and (BH) max of 1068 kJ/m3 at 2 K. [ABSTRACT FROM AUTHOR]

The Tb–Co-Ga system has been investigated at 870 K by X-ray powder and microprobe elemental analyses. The existence of the known compounds TbGo 5 Ga 7 (ScFe 6 Ga 6 -type), Tb 2 Co 3 Ga 9 (Y 2 Co 3 Ga 9 -type), TbCoGa 5 (HoCoGa 5 -type), Tb 6 Co 7 Ga 21 (Ho 6 Co 7 Ga 21 -type), Tb 4 Co 3 Ga 16 (Sm 4 Co 3 Ga 16 -type), Tb 2 CoGa 8 (Ho 2 FeGa 8 -type), TbCo 3~2.8 Ga 2~2.2 (HoNi 2.6 Ga 2.4 -type), Tb 3 Co 7~5.4 Ga 2~3.6 (CeNi 3 -type), TbCo 1~1.67 Ga 1~0.33 (TiNiSi-type), Tb 2 CoGa 3 (Lu 2 CoGa 3 -type), Tb 3 Co 3 Ga (W 3 CoB 3 -type), Tb 2 Co 2 Ga (Mo 2 NiB 2 -type) and Tb 6 Co 2~2.2 Ga 1~0.8 (Ho 6 Co 2 Ga-type) has been confirmed, the TbCo 6.7-5.5 Ga 0.3-1.5 (TbCu 7 -type) is suggested, meanwhile new MgZn 2 -type TbCo 1.33 Ga 0.67 , Er 12 Ni 5 Ga 3 -type Tb 12 Co 5~5.5 Ga 3~2.5 and Sm 26 Co 11 Ga 6 -type Tb 26 Co 5~9.4 Ga 12~7.6 were detected at 870 K. Quasi-binary solid solutions were detected for Tb 2 Co 17 , TbCo 5 , Tb 2 Co 7 , TbCo 3 , TbCo 2 , TbGa 2 and Tb 5 Ga 3 at 870, while no appreciable solubility was observed for the other binary compounds in the Tb–Co-Ga system. Magnetic properties of the Tb 4 Co 3 Ga 16 , Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 compounds have been studied this work. Tb 4 Co 3 Ga 16 is antiferromagnetic, while Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 exhibit mixed ferro-antiferromagnetic ordering. Additionally, new Er 12 Ni 5 Ga 3 -type {Dy, Ho} 12 Co 5.5 Ga 2.5 , Sm 26 Co 11 Ga 6 -type Gd 26 Co 9.2 Ga 7.8 , Dy 26 Co 8 Ga 9 , Er 26 Co 5 Ga 12 compounds and Cr 5 Ga 3 -type Dy 5 Co 0.9 Ga 2.1 quasi-binary solid solution have been detected in this work. The Tb–Co-Ga system has been investigated at 870 K by X-ray powder and microprobe elemental analyses. The existence of the known compounds TbGo 5 Ga 7 (ScFe 6 Ga 6 -type), Tb 2 Co 3 Ga 9 (Y 2 Co 3 Ga 9 -type), TbCoGa 5 (HoCoGa 5 -type), Tb 6 Co 7 Ga 21 (Ho 6 Co 7 Ga 21 -type), Tb 4 Co 3 Ga 16 (Sm 4 Co 3 Ga 16 -type), Tb 2 CoGa 8 (Ho 2 FeGa 8 -type), TbCo 3~2.8 Ga 2~2.2 (HoNi 2.6 Ga 2.4 -type), Tb 3 Co 7~5.4 Ga 2~3.6 (CeNi 3 -type), TbCo 1~1.67 Ga 1~0.33 (TiNiSi-type), Tb 2 CoGa 3 (Lu 2 CoGa 3 -type), Tb 3 Co 3 Ga (W 3 CoB 3 -type), Tb 2 Co 2 Ga (Mo 2 NiB 2 -type) and Tb 6 Co 2~2.2 Ga 1~0.8 (Ho 6 Co 2 Ga-type) has been confirmed, the TbCo 6.7-5.5 Ga 0.3-1.5 (TbCu 7 -type) is suggested, meanwhile new MgZn 2 -type TbCo 1.33 Ga 0.67 , Er 12 Ni 5 Ga 3 -type Tb 12 Co 5~5.5 Ga 3~2.5 and Sm 26 Co 11 Ga 6 -type Tb 26 Co 5~9.4 Ga 12~7.6 were detected at 870 K. Quasi-binary solid solutions were detected for Tb 2 Co 17 , TbCo 5 , Tb 2 Co 7 , TbCo 3 , TbCo 2 , TbAl 2 and Tb 5 Ga 3 at 870, while no appreciable solubility was observed for the other binary compounds in the Tb–Co-Ga system. Magnetic properties of the Tb 4 Co 3 Ga 16 , Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 compounds have been studied and are presented in this work. New Er 12 Ni 5 Ga 3 -type {Dy, Ho} 12 Co 5.5 Ga 2.5 , Sm 26 Co 11 Ga 6 -type Gd 26 Co 9.2 Ga 7.8 , Dy 26 Co 8 Ga 9 , Er 26 Co 5 Ga 12 compounds and Cr 5 Ga 3 -type Dy 5 Co 0.9 Ga 2.1 quasi-binary solid solution have been detected in this work. Image 1 • Tb–Co-Ga system was obtained at 870 K. • Ten known ternary terbium cobalt gallides were confirmed in Tb–Co-Ga. • Three new ternary compounds were detected in Tb–Co-Ga. • Five new ternary compounds were detected in R -Co-Ga. • Magnetic properties of five terbium cobalt gallides were investigated. [ABSTRACT FROM AUTHOR]

Three rare-earth oxide selenates Ln 2 O 2 SeO 4 (Ln = La, Pr, Nd) have been prepared via double-exchange solid-state reactions between respective LnOCl oxyhalides and potassium selenate. This approach succeeded to obtain single-phase specimens of La 2 O 2 SeO 4 and Nd 2 O 2 SeO 4 , previously known as transients upon thermal decomposition of the corresponding selenates, as well as a new compound Pr 2 O 2 SeO 4. Refinement of their crystal structures from powder X-ray diffraction data confirmed previous attributions to the grandreefite (Pb 2 F 2 SO 4) structure type observed also for the Ln 2 O 2 SO 4 oxide sulfates. According to polythermic X-ray studies, La 2 O 2 SeO 4 is stable until at least 700 °C. All compounds were characterized by infrared and X-ray photoelectron spectroscopy. Double exchange reactions of rare-earth opxyhalides LnOCl (Ln = La, Pr, Nd) and potassium selenate lead to pure oxide selenates Ln 2 O 2 SeO 4 formerly supposed as transients upon decomposition of Ln 2 (SeO 4) 3 ⋅8H 2 O. Image 1 • Three new Ln 2 O 2 SeO 4 compounds have been prepared (Ln = La, Pr, Nd). • The new compounds are isostructural to Ln 2 O 2 SO 4. • Double-exchange solid-state synthesis is an only approach to these compounds. [ABSTRACT FROM AUTHOR]

The crystal structure, magnetic, and microwave absorption properties of the (Nd1−xLax)2Fe14B system have been investigated. The La2Fe14B compound was successfully synthesized and refined, giving a tetragonal structure, space group P42/mnm with the Nd2Fe14B-type structure. The crystal structure parameters of the (Nd1−xLax)2Fe14B compounds were determined by full-profile Rietveld refinements. The results revealed that all intermediate alloys form a continuous solid solution. The normalized lattice parameters of the (Nd1−xLax)2Fe14B compounds increase linearly with an increase of La concentration. Based on the results of DSC measurements and X-ray powder diffraction examinations, the phase diagram of the Nd2Fe14B-La2Fe14B system has been constructed. The remanence (Mr) and coercivity (Hc) of (Nd1−xLax)2Fe14B (x = 0.00, 0.10, 0.20, 0.30, and 0.40) gradually decrease. The highest reflection loss is − 29.8, − 27.4, − 24.1, − 18.6, and − 14.2 dB at 9.8, 8.9, 7.5, 6.9, and 6.5 GHz, respectively. The absorption peak shifts toward from higher frequency region to lower frequency region and the absorption bandwidth widens with the increase of the La substitution. [ABSTRACT FROM AUTHOR]

Abstract Magnetic ordering of the polycrystalline Lu 14 Ni 3 In 3 -type Gd 14 Ni 3 Al 3 and Tb 14 Ni 3 Al 3 (space group P 4 2 / nmc , N 137, tP 80) has been studied by magnetization, heat capacity and neutron diffraction study. The magnetization and heat capacity measurements of Gd 14 Ni 3 Al 3 reveal the antiferromagnetic ordering at 62 K and low-temperature spin-reorientation transition at 42 K. Neutron diffraction study in zero applied magnetic field indicates non-collinear antiferromagnetic ordering of Tb 14 Ni 3 Al 3. It exhibits abc -antiferromagnetic ordering with magnetic space group P2 1 ′/c′ (wave vector K 0 = [0, 0, 0]) below 47 K and slight reorientation of terbium magnetic moments between 16 K and 36 K. Graphical abstract Image 1 Highlights • {Gd, Tb} 14 Ni 3 Al 3 demonstrate pure antiferromagnetic ordering. • Gd 14 Ni 3 Al 3 exhibits antiferromagnetic transitions at T N = 62 K and T m = 42 K. • Gd 14 Ni 3 Al 3 shows field induced weak ferromagnetism. • Tb 14 Ni 3 Al 3 exhibits abc -AF ordering with wave vector K 0 = [0, 0, 0] in zero field. • abc -AF ordering of Tb 14 Ni 3 Al 3 meets to magnetic space group P2 1 ′/c′. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel {Gd, Tb, Lu} 14 Ni 3 Al 3 belong to tetragonal Lu 14 Co 3 In 3 -type structure. • Y 14 Co 3 Al 3 is paramagnetic down to 2 K. • Gd 14 Co 3.2 Al 2.8 exhibits ferro-antiferromagnetic ordering. • {Tb, Dy} 14 {Co, Ni} 3 Al 3 demonstrate pure antiferromagnetic ordering. • {Tb, Dy} 14 {Co, Ni} 3 Al 3 AF show field induced slight ferromagnetism. Abstract The crystal structure of new Lu 14 Co 3 In 3 -type {Gd, Tb, Lu} 14 Ni 3 Al 3 compounds (P 4 2 / nmc. N 137, tP 80) has been established using powder X-ray diffraction studies with cell parameters a = 0.95765(2) nm, c = 2.30214(5) nm for Gd 14 Ni 3 Al 3 , a = 0.95012(5) nm, c = 2.28190(10) nm for Tb 14 Ni 3 Al 3 and a = 0.92604(2) nm, c = 2.23350(4) nm for Lu 14 Ni 3 Al 3. Magnetic properties of the polycrystalline Y 14 Co 3 Al 3 , Gd 14 Co 3.2 Al 2.8 and {Tb, Dy} 14 {Co, Ni} 3 Al 3 have been studied by magnetization measurements. Y 14 Co 3 Al 3 is paramagnetic down to 2 K, Gd 14 Co 3.2 Al 2.8 exhibits ferro-antiferromagnetic ordering, while {Tb, Dy} 14 {Co, Ni} 3 Al 3 show field sensitive pure antiferromagnetic ordering with field induced slight ferromagnetism. Heat capacity measurements (in zero applied magnetic field and field of 50 kOe) confirm metamagnetic-like transitions of Tb 14 Ni 3 Al 3 and Dy 14 Ni 3 Al 3. [ABSTRACT FROM AUTHOR]

The scientific and technological principles were presented for the production of electrochemical nanocomposites from a nickel matrix and lanthanum fluoride and boride on electrode welding consumables. It was shown that rare-earth nanocomposites improve the impact toughness and microstructure of welds of high-strength cold-resistant and cryogenic steels at low temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • GdNi 4 B, GdNi 4 In, GdCo 4 Al and DyCo 4.6 Si 0.4 prepared via arc-furnace melting/annealing. • GdNi 4 B and GdNi 4 In show dominant ferromagnetic ordering of Gd sublattice. • GdCo 4 Al and DyCo 4.6 Si 0.4 exhibit HT dominant ferromagnetic ordering of Co sublattice. • GdCo 4 Al and DyCo 4.6 Si 0.4 show LT with dominant ordering of rare earth sublattice. • GdNi 4 In exhibits largest magnetocaloric effect from GdNi 4 {B, Al, Ga, Si, In} compounds. The polycrystalline CeCo 4 B-type GdNi 4 B (space group P 6/ mmm , N 191, hP 12), CaCu 5 -type GdCo 4 Al and DyCo 4.6 Si 0.4 (space group P 6/ mmm , N 191, hP 6) and MgCu 4 Sn-type GdNi 4 In (space group F -43 m , N 216, cF 24) were prepared by arc melting with following annealing. The magnetic ordering and magnetocaloric effects of these compounds have been investigated using magnetic measurements in fields up to 90 kOe. GdNi 4 B and GdNi 4 In show dominant ferromagnetic ordering of Gd sublattice with T C of 39 K and 24 K, respectively with magnetic entropy change of −11.3 J/kg·K for GdNi 4 B and −11.8 J/kg·K for GdNi 4 In for a field change of 50 kOe. GdCo 4 Al and DyCo 4.6 Si 0.4 exhibit high-temperature dominant ferromagnetic ordering of Co sublattice with low-temperature spin-reorientation transformation of magnetic ordering and dominant ordering of rare earth sublattice in width temperature interval. In a field change of 50 kOe, the compensation temperature of DyCo 4.6 Si 0.4 is followed via table-like magnetic entropy change of −1.0 J/kg·K at ∼40–240 K, while GdCo 4 Al exhibits magnetic entropy change of around −0.6 J/kg·K at ∼150–300 K. [ABSTRACT FROM AUTHOR]

Two-dimensional ferrovalley magnetic materials have attracted much attention due to the applications in valley-based nonvolatile random access memories and valley filters. In this work, using first-principles calculations, we predict a promising class of bipolar magnetic semiconductors, namely non-Janus GdXY(X≠Y=Cl,Br,I) monolayers, which exhibit excellent mechanical and thermal stability, large magnetic moment (8 μ B /Gd), and high Curie temperature (above 450 K). When magnetized along the ± z direction, a spontaneous valley polarization can be observed in non-Janus GdXY. Due to the non-zero Berry curvature, the anomalous Hall effect will be able to be observed in non-Janus GdXY. In addition, the system transforms into a semi-semiconductor from a bipolar magnetic semiconductor with increasing biaxial tensile strain. Under the strain of -4%∼+4%, the ferrovalley characteristics can be well maintained. Our findings not only reveal that non-Janus GdXY is a novel room-temperature ferrovalley semiconductor material, but also provide a new platform for designing spintronics and valley electronics devices. • Non-Janus GdXY monolayers are novel two-dimensional rare-earth ferro-valley materials. • Non-Janus GdXY monolayers exhibit high Curie temperatures above 450 K. • Non-Janus GdXY monolayers have large valley splitting. • Non-Janus GdXY monolayers provide a new platform for realizing the anomalous Hall effect. • The ferro-valley characteristics of non-Janus GdXY monolayers can be well maintained under the biaxial strain of -4%∼+4%. [ABSTRACT FROM AUTHOR]

We calculated electronic structure of Ce 2 Rh 3 Ga 9 , Ce 2 Ru 3 Ga 9 , La 2 Ir 3 Al 9 and Ce 2 Ir 3 Al 9 compounds and we found that Ce 2 Ir 3 Al 9 may exhibit strong topological insulator state according to Z 2 index estimation based on parity algorithm and shape of band structure near Fermi level. The same algorithm shows strong topological insulator state for La 2 Ir 3 Al 9 and Ce 2 Rh 3 Ga 9 compounds, but their band structure near Fermi level is more like semimetallic one. Ce 2 Ru 3 Ga 9 is a normal metal. Our calculations show no magnetic ordering for studied compounds. We also measured the XPS (X-ray Photoelectron Spectroscopy) spectra for these materials, and compared the valence band with simulated spectra, where good agreement was found. Core level states were also investigated and compared with Mulliken population analysis results. According to our measurements and calculations, the highest Ce valence is observed for Ce 2 Ir 3 Al 9 whereas for Ce 2 Rh 3 Ga 9 and Ce 2 Ru 3 Ga 9 the Ce valence is smaller. Hybridization between conduction electrons and 4 f states is very small, and for Ce 2 Ru 3 Ga 9 essentially negligible. [Display omitted] • The first electronic structure calculations with FPLO method of Ce 2 Rh 3 Ga 9 , Ce 2 Ru 3 Ga 9 , La 2 Ir 3 Al 9 and Ce 2 Ir 3 Al 9 have been reported. • The calculations show, that in the case of Ce 2 Ir 3 Al 9 the hour glass-like structure is visible at Γ point, but this structure is visible slightly above the ϵ F. • We found that Ce 2 Ir 3 Al 9 may exhibit strong topological insulator state. • Our calculations show no magnetic ordering for studied compounds. • Moreover, we also found that hybridization of 4 f and conduction electrons is small for Ce 2 Ir 3 Al 9 and Ce 2 Rh 3 Ga 9 and close to zero for Ce 2 Ru 3 Ga 9. [ABSTRACT FROM AUTHOR]

Structural and magnetic properties of an intermetallic Ho 2 Rh 3 Ge compound have been investigated in this paper. We report the observation of large magnetocaloric effect (MCE) in Ho 2 Rh 3 Ge from the characterization of magnetism isotherms. The Rietveld refinement of powder X-ray diffraction revealed that Ho 2 Rh 3 Ge crystallizes in a rhombohedral Laves phase structure (space group R 3 ̄ m , hR18). It exhibits ferromagnetic order below the Curie temperature T C = 13 K. Around T C , maximum value of entropy change −Δ S m = 25.4 J kg−1 K−1 was observed for a change of magnetic field 0−8 T. The obtained refrigeration capacity (relative cooling power) for a change of magnetic field from 0 8 T is 497(664) J.kg−1. The second – order magnetic phase transition in Ho 2 Rh 3 Ge is confirmed from Arrott plots, universal scaling plots of magnetic entropy changes, and also from the field dependence of the magnetic entropy change. • A polycrystalline Ho 2 Rh 3 Ge has been synthesized by acr-melting method. • Structural and Magnetic of Ho 2 Rh 3 Ge have been studied. • Large reversible magnetocaloric effect has been observed in ternary Laves phase compound Ho 2 Rh 3 Ge. [ABSTRACT FROM AUTHOR]

• Single crystal growth, thermodynamic and transport properties of EuAg 2 Ge 2 are reported. • Two successive antiferromagnetic transitions are observed in the compound around 6.2 K and 8.3 K. • Isothermal magnetization below T N for H ‖ c reveals a metamagnetic transition at a critical field of 1.4 T. • The magnetoresistance for H ‖ c exhibits a broad maximum around the critical field of metamagnetic transition. Here, we report the crystallographic, thermodynamic, and magnetotransport properties of flux grown EuAg 2 Ge 2 single crystals using X-ray diffraction, anisotropic magnetic susceptibility, and magnetization, heat capacity, electrical resistivity, and magnetoresistance measurements. The room temperature powder X-ray diffraction pattern confirms that EuAg 2 Ge 2 crystallizes in a body-centered tetragonal ThCr 2 Si 2 –type structure (space group I4 / mmm) with lattice parameters, a = 4.401 Å and c = 10.845 Å. The magnetic susceptibility data reveal two subsequent antiferromagnetic transitions at T N1 ∼ 8.3 K, and T N2 ∼ 6.2 K. For H ‖ c at T = 5 K, the magnetization data show the spin-flop like metamagnetic transition around the critical field of 1.4 T. The existence of antiferromagnetic transitions is further confirmed by the heat capacity measurements, which display two anomalies around T N1 = 8.3 K and T N2 = 6.1 K. The electrical resistivity data show the metallic behavior of the compound, which is best described by the Bloch-Grüneisen model above 30 K. At low temperatures, the antiferromagnetic transition manifests through a slight upturn around 8 K, followed by a sharp drop in the resistivity data. The transverse magnetoresistance (MR) measured for H ‖ c below T N first increases, showing a broad maximum at critical field strength that shifts towards lower fields with increasing temperature. With further increasing fields beyond the maximum, MR decreases, and changes its value from positive to negative. The evolution of MR from positive to negative could be associated with the metamagnetic transition in EuAg 2 Ge 2. In the paramagnetic region, MR remains negative across the entire field range. [ABSTRACT FROM AUTHOR]

The composite coatings containing borides and carbides were fabricated on a Ti-6Al-4V alloy by CO2 laser cladding of the Al3Ti-Cu-TiB2-C mixed powders. Microscopic analysis revealed that with decreasing of the C content, the crystals such as the titanium borides and the Ti5Si3/TiC eutectics had more time to grow up. Addition of the proper Y2O3 content would retard the growth of the crystals in a certain extent, resulting in a fine microstructure,also, it was noted that Cu was able to promote growth of the crystals in laser induced molten pool. [ABSTRACT FROM AUTHOR]

Abstract Magnetic ordering of the polycrystalline YNi 4 Si-type YNi 4 Si, disordered YNi 4 Si-type TbNi 4 Si and NdNi 3 CoSi (space group Cmmm , N 65, oC 12), and CaCu 5 -type NdNi 3 T Si ( T = Mn, Fe, Cu) and Sm 1-x Tb x Ni 3 FeSi (x = 0.25 and 0.5) solid solutions (space group P6/mmm , N 191, hP 6) have been studied by magnetization measurements. Down to 2 K, YNi 4 Si is paramagnetic, whereas TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi and NdNi 3 CuSi show ferromagnetic ordering (T C ) at 30 K, 71 K, 120 K, 20 K and 5.6 K and field sensitive transitions (T m ) at 10 K, 43 K, 63 K, 16 K and 3.8 K, respectively. Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi show ferromagnetic-antiferromagnetic transformations below ferromagnetic ordering at 166 K and 120 K, respectively. Magnetocaloric effect (MCE) of TbNi 4 Si, NdNi 3 {Mn, Co, Cu}Si, Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi compounds were estimated in terms of isothermal magnetic entropy change (ΔS m ). Among these compounds, TbNi 4 Si and NdNi 3 CuSi show maximal MCE with ΔS m of − 9.95 J/kg K (RCP 50 kOe ~ 180 J/kg) at 26–30 K and − 6.29 J/kg K (RCP 50 kOe ~ 31 J/K) at 6 K in a field change of 50 kOe, respectively. Below T m , TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi, NdNi 3 CuSi and Sm.5 Tb.5 Ni 3 FeSi show hard magnetic properties with coercivity of 2.2 kOe, 4.8 kOe, 4.8 kOe, 9.5 kOe, 1 kOe and 15 kOe at 2 K, respectively. Sm.75 Tb.25 Ni 3 FeSi shows a coercivity of 39 kOe at 40 K. Graphical abstract The magnetic ordering of the polycrystalline YNi 4 Si-type YNi 4 Si, disordered YNi 4 Si-type TbNi 4 Si and NdNi 3 CoSi (space group Cmmm , N 65, oC 12), and CaCu 5 -type NdNi 3 T Si ( T = Mn, Fe, Cu) and Sm 1-x Tb x Ni 3 FeSi (x = 0.25 and 0.5) solid solutions (space group P6/mmm , N 191, hP 6) have been studied by magnetization measurements. Down to 2 K, YNi 4 Si is paramagnetic, whereas TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi and NdNi 3 CuSi show ferromagnetic ordering (T C ) at 30 K, 71 K, 120 K, 20 K and 5.6 K and field sensitive transitions (T m ) at 10 K, 43 K, 63 K, 16 K and 3.8 K, respectively. Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi show ferromagnetic-antiferromagnetic transformations below ferromagnetic ordering at 166 K and 120 K, respectively. Among these solid solutions, TbNi 4 Si and NdNi 3 CuSi show maximal MCE with ΔS m of −9.95 J/kg K (RCP 50 kOe ~ 180 J/kg) at 26–30 K and −6.29 J/kg K (RCP 50 kOe = 31 J/K) at 6 K for NdNi 3 CuSi for a field change of 50 kOe, respectively. Below T m , TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi, NdNi 3 CuSi and Sm.5 Tb.5 Ni 3 FeSi are permanent magnets with coercivity of 2.2 kOe, 4.8 kOe, 4.8 kOe, 9.5 kOe, 1 kOe and 15 kOe at 2 K, respectively. Sm.75 Tb.25 Ni 3 FeSi shows a coercivity of 39 kOe at 40 K. fx1 Highlights • Disordered YNi 4 Si-type as-cast TbNi 4 Si and NdNi 3 CoSi show complex F-AF ordering. • CaCu 5 -type NdNi 3 {Mn, Fe, Cu}Si and Sm 1-x Tb x Ni 3 FeSi show complex F-AF ordering. • As-cast TbNi 4 Si and NdNi 3 CuSi show maximal MCE from these compounds. • NdNi 3 CoSi shows a coercivity of 9.5 kOe with M res /fu = 1.77 μ B at 2 K. • Sm.75 Tb.25 Ni 3 FeSi exhibits a coercivity of 39 kOe with M res /fu = 0.49 μ B at 40 K. [ABSTRACT FROM AUTHOR]

X-ray analysis of the YFe 3 (BO 3 ) 4 single crystal revealed different behavior of parameters of the crystal cell with an increase in temperature from 25 to 500 K. The parameters a and b initially increase monotonically and then rise sharply in the range between 360 and 380 K, which corresponds to the structural phase transition. The parameter c initially decreases linearly upon heating and then begins to increase, passing through a minimum at 90 K. In the interval of 200–500 K the parameter c grows linearly and does not undergo anomalies at the structural phase transition. The results of Mössbauer measurements at 57 Fe nuclei in the paramagnetic phase of YFe 3 (BO 3 ) 4 correlate well with the XRD data, but they do not separate the two structural states of iron ions Fe1 and Fe2 arising in the P 3 1 21 phase during the structural phase transition. The temperature of the magnetic phase transition T N  = 39.42(16) K is established, below which the iron ions form a 3D magnetic order of the Heisenberg type. The calculated “Mössbauer” Debye temperature Θ M  = 340(2) K turned out to be three times lower than the Debye temperature of the entire crystal lattice T D  = 1020 K. Mössbauer data indicate a weak bonding between the helicoidal chains of iron and the rest of the crystal lattice. [ABSTRACT FROM AUTHOR]

The Gd-Co-Al system has been investigated at 870/1070 K by X-ray and elemental EDS analyses. The existence of the known compounds Gd 2 Co 3 Al 9 (Y 2 Co 3 Ga 9 -type), Gd 3 Co 4.5 Al 11.5 (Gd 3 Co 4.6 Al 11 ) (Gd 3 Ru 4 Al 12 -type), Gd 3 Co 6–7.4 Al 3–1.6 (CeNi 3 -type), GdCo 1.15–0.65 Al 0.85–1.35 (MgZn 2 -type), Gd 2 Co 2 Al (Mo 2 NiB 2 -type) and Gd 3 Co 3.5–3.25 Al 0.5–0.75 (W 3 CoB 3 -type) has been confirmed at 870/1070 K. Structure types have been determined for Gd 2 Co 6 Al 19 (U 2 Co 6 Al 19 -type), Gd 7 Co 6 Al 7 (Pr 7 Co 6 Al 7 -type), Gd 6 Co 2–2.21 Al 1–0.79 (Ho 6 Co 2 Ga-type) and Gd 14 Co 3.2 Al 2.8 (Gd 14 Co 2.58 Al 3.42 at 970 K) (Lu 14 Co 3 In 3 -type). The structures of Gd 6 Co 2 Al, Gd 6 Co 2.21 Al 0.79 and Gd 14 Co 2.58 Al 3.42 flux-grown at 970 K have been refined from the single crystal X-ray diffraction data. Additionally, new ternary compounds Gd 2 Co 5.7–5.3 Al 1.3–1.7 (Er 2 Co 7 -type) and ~Gd 58 Co 20 Al 22 (unknown type structure) have been identified. Quasi-binary solid solutions were detected for Gd 2 Co 17 , GdCo 5 , Gd 2 Co 7 , GdCo 3 , GdCo 2 and GdAl 2 at 870/1070 K, while no appreciable solubility was observed for the other binary compounds in the Gd-Co-Al system. Magnetic properties of the Gd 2 Co 3 Al 9 , Gd 3 Co 4.6 Al 11 , Gd 7 Co 6 Al 7 , Gd 6 Co 2.2 Al 0.8 and Gd 14 Co 2.58 Al 3.42 compounds have been studied and are presented in this work. Gd 6 Co 2.2 Al 0.8 , Gd 3 Co 4.6 Al 11 , Gd 7 Co 6 Al 7 and Gd 14 Co 2.58 Al 3.42 order ferromagnetically, while Gd 2 Co 3 Al 9 displays antiferromagnetic transition. Additionally, {Y, Sm, Tb - Tm} 2 Co 6 Al 19 (U 2 Co 6 Al 19 -type), Yb 2 Co 3 Al 9 (Y 2 Co 3 Ga 9 -type), {Y, Sm, Tm, Yb} 3 Co 4.6 Al 11 (Gd 3 Ru 4 Al 12 -type) and Tb 7 Co 6 Al 7 (Pr 7 Co 6 Al 7 -type) compounds have been synthesized and investigated. [ABSTRACT FROM AUTHOR]

We present results of neutron diffraction on single crystals of several equiatomic ternary compounds of rare-earth elements with palladium and bismuth, crystallizing with cubic MgAgAs-type structure (half-Heusler phases). Band structure calculations showed that many members of that family possess electronic band inversion, which may lead to occurrence of topological insulator or topological semimetal. But even for the compounds without intrinsic band inversion another way of topologically non-trivial state realization, through a specific antiferromagnetic order, has been theoretically proposed. Our results show that the antiferromagnetic structures of all studied bismuthides are characterized by the propagation vector, allowing for antiferromagnetic topological insulator state. Therefore, the antiferromagnetic representatives of half-Heusler family are excellent candidates for extended investigations of coexistence of superconductivity, magnetic order and non-trivial topology of electronic states. [ABSTRACT FROM AUTHOR]

In the work reported in this paper, the temperature dependence of the magnetic hyperfine field ( B h f ) at 140 Ce nuclei replacing Pr atoms in PrMn 2 Ge 2 compound was measured by the perturbed angular correlation technique to complete the sequence of measurements in REMn 2 Ge 2 (RE = La, Ce, Pr, Nd). Results show an anomalous behavior different from the expected Brillouin curve. A model was used to fit the data showing that the Ce impurity contribution ( B h f i m p ) to B h f is negative for NdMn 2 Ge 2 below 210 K. The impurity contribution ( B h f i m p ) at 0 K for all compounds is much smaller than that for the free Ce 3+ , showing that the 4 f band of Ce is more likely highly hybridized with 5 d band of the host. Results show that direction of the localized magnetic moment at Mn atoms strongly affects the exchange interaction at Ce impurities. [ABSTRACT FROM AUTHOR]

The magnetic ordering of Mo 2 NiB 2 -type Sm 2 Co 2 Al and Sm 2 Co 2 Ga ( Immm , No. 71, oI 10) compounds has been established using bulk magnetic measurements. Polycrystalline Sm 2 Co 2 Al and Sm 2 Co 2 Ga undergo ferromagnetic transitions (T C ) at 50 K and 62 K, respectively, and low-temperature field induced transitions (T m ) around 14 K and 16 K (in a field of 10 kOe), respectively. Between T C and T m Sm 2 Co 2 Al and Sm 2 Co 2 Ga are soft ferromagnets. Below T m Sm 2 Co 2 Al and Sm 2 Co 2 Ga exhibit permanent magnet properties with a residual magnetization per samarium of 0.38 μ B and 0.36 μ B , respectively, and a large coercive field of 69 kOe and 72 kOe, respectively, at 5 K. The magnetocaloric effects of Sm 2 Co 2 Al and Sm 2 Co 2 Ga were calculated in terms of isothermal magnetic entropy change and they reach maximum values of −1.62 J/kg K and −1.31 J/kg K for a field change of 50 kOe at 50 K and 58 K, respectively. Low temperature magnetic ordering with enhanced anisotropy in Sm 2 Co 2 Al and Sm 2 Co 2 Ga is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +1.63 J/kg K and +1.06 J/kg K for a field change of 50 kOe at 10 K and 8 K, respectively. [ABSTRACT FROM AUTHOR]

In this work, we report the magnetic and magnetocaloric properties of the Gd 1−y Pr y Ni 2 compounds from both experimental and theoretical points of view. It is worth noting that this series shows a variety of magnetic arrangements depending on the Pr concentration, including paramagnetism, ferrimagnetism and ferromagnetism. Our experimental work consists of the systematic analysis of the magnetic properties of the compounds with y = 0.0, 0.25, 0.5, 0.75 and 1.0, which includes temperature and magnetic field dependence of the magnetization, heat capacity and isothermal entropy change obtained by isothermal magnetization curves. Also, we developed a model Hamiltonian, which takes into account the exchange interactions among Gd-Gd, Gd-Pr and Pr-Pr ions, the Zeeman interaction for both ions and the crystalline electrical field interaction for the Pr ions. We systematically investigated the magnetic properties of the series and obtained a good agreement when compared with our experimental data. [ABSTRACT FROM AUTHOR]