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—The present work surveys literature data related to the study of iron–rhodium-based (Fe–Rh) alloys. The crystal, magnetic, and electronic properties of the FeRh alloy and FeRh-based materials in the form of both bulk, thin-film, and nano-structured objects are considered. Peculiarities of the first-order antiferromagnet–ferromagnet transition are analyzed, and various explanations of its nature are discussed. Different approaches to the preparation of the iron–rhodium-based alloys are reported; an analysis of the effect of heat treatment conditions on the properties of the material and their reproducibility in measuring the magnetocaloric properties is performed. Causes for the record values of the magnetocaloric effect (MCE) observed for the material are shown, and prospects of the application of this alloy in magnetic refrigeration technology, medicine, electronics, and magnetic data recording technology are discussed.

The electronic structures of V-intercalated TiSe2 and substitutionally doped dichalcogenides Ti1-xVxSe2 have been studied using soft X-ray photoelectron, resonant photoelectron, and absorption spectroscopies. In the case of the substitution of Ti by V, the formation of coherently oriented structural fragments VSe2 and TiSe2 is observed and a small charge transfer between these fragments is found. Intercalation of the V atoms into TiSe2 leads to charge transfer from the V atoms to the Ti atoms with the formation of covalent complexes Ti-Se-3-V-Se-3-Ti.

Complex incommensurate magnetic structures of Tb3Ni and Ho7Rh3 compounds have been analyzed using the magnetic superspace group approach. It has been established that the high-temperature incommensurate magnetic structure of Tb3Ni is described by the magnetic superspace group P1121/a1'(ab0)0ss and the incommensurate magnetic structure of Ho7Rh3 is described by the magnetic superspace group $$P{{6}_{3}}1{\kern 1pt} '\left( {00g} \right)hs.$$ Using the example of the Tb3Ni and Ho7Rh3 compounds, it is shown that the magnetic superspace groups formalism is the most efficient approach when establishing and describing complex incommensurate magnetic structures.

Spin susceptibility and low-frequency dynamics of uranium $5f$ electrons have been investigated by nuclear magnetic resonance (NMR) on the $^{14}\mathrm{N}$ nuclei in paramagnetic and magnetically ordered phases for single crystalline and polycrystalline samples of uranium mononitride (UN). NMR spectra, shifts of the $^{14}\mathrm{N}$ NMR lines, and the spin-lattice relaxation times ${T}_{1}$ have been obtained in the temperature range $T=10--760\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ in magnetic field $B=92.8\phantom{\rule{0.16em}{0ex}}\mathrm{kOe}$. It is shown that in the UN paramagnetic phase, temperature dependence of the $^{14}\mathrm{N}$ NMR line shift is proportional to the spin susceptibility of the uranium $5f$ electrons. Joint analysis of NMR and magnetic susceptibility data allows us to determine temperature dependence of spin fluctuation energy ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{nmr}}(T)$ of the uranium $5f$ electrons and to demonstrate that its temperature variation is close to $\mathrm{\ensuremath{\Gamma}}(T)\ensuremath{\propto}{T}^{0.5}$ dependence which is characteristic of the concentrated Kondo systems above the coherent state formation temperature. In the magnetically ordered UN phase the $^{14}\mathrm{N}$ NMR spectra consist of several lines that can be explained in terms of the model of type $I$ antiferromagnetic order corresponding to $1k$ structure in the presence of magnetic domains.

The research was supported by the Russian Science Foundation (project 16-12-10004). The authors are grateful for the contributions made by our colleagues G. S. Zakharova, A. S. Konev, K. I. Borodin, Z. A. Phatakhova, A. M. Murzakaev, and V. S. Gaviko. The X-ray investigation and magnetic measurements have been performed in the Collaborative Access Center of M. N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia.

The electronic structures of V-intercalated TiSe

An ac photopyroelectric calorimeter has been used to study the critical behavior of the magnetic transitions in Dy3Co measuring thermal diffusivity, specific heat and thermal conductivity, at low temperature. There are two phase transitions, both of which present singularities in the three variables. The antiferromagnetic to paramagnetic phase transition at ≈ 42 K complies with the short range, isotropic universality class, 3D-Heisenberg (αexp = −0.13 for specific heat, bexp = −0.15 for thermal diffusivity, αtheor = btheor = −0.134). In the case of the lower transition where there is a rearrangement of the antiferromagnetic spin ordering at ≈ 32 K the critical behavior shows a deviation from isotropy. These results are linked to magnetic measurements already found in literature.

Co-doped TiO2 is one of the most extensively studied oxides for applying as dilute magnetic semiconductors due to its room temperature magnetism. Here we present results of the studies of Ti0.97Co0.03O2 nanopowders synthesized by hydrothermal method by means of X-ray diffraction, soft X-ray absorption spectroscopy (Ti L2,3 and Co L2,3 spectra), hard X-ray absorption spectroscopy (Co K spectra), and 1s3p resonant inelastic X-ray scattering at the Co K edge. According to X-ray diffraction data and Ti L2,3 X-ray absorption spectra, all the samples before the thermal treatment exhibit anatase structure with substantial amount of amorphous phase. After annealing the Ti0.97Co0.03O2 samples in vacuum or hydrogen at 700oC, the anatase structure persists while amorphous phase contribution is eliminated. Surface sensitive soft X-ray absorption Co L2,3 spectroscopy revealed only Co2+ ions tetrahedrally coordinated by oxygen ions and no sign of metallic Co. Co2+ tetrahedral sites (instead of typical octahedral ones) ...

The charge states of the cobalt ions in TiO2 nanopowders with the anatase lattice are studied by soft X-ray absorption spectroscopy. It is found that, at a low cobalt impurity concentration (1.8 at %), the cobalt ions with an oxidation state 2+ are mainly located in the tetrahedral (T d ) environment of oxygen ions. Amorphous titanium dioxide exists on the sample surface before heat treatment. Annealing in vacuum or hydrogen leads to the enrichment of the nanoparticle surfaces with Co2+ ions, a change in the coordination of the remaining part of cobalt ions from octahedral to tetrahedral, stabilization of the anatase structure, and the disappearance of the amorphous phase. The crystal lattice of the samples with a relatively high cobalt concentration (12 at %) is distorted, and annealing does not cause the disappearance of the amorphous phase of TiO2. Cobalt is reduced to its metallic state upon hydrogen annealing of the samples with a high cobalt concentration.

Cobalt-doped anatase Ti1–xCoxO2 (0 < x ≤ 0.04) nanopowders (with a particle size of 30–40 nm) were produced by the hydrothermal synthesis method. Morphology, structure, and thermal stability of the synthesized compounds were examined using transmission electron microscopy, infrared spectroscopy, and X-ray diffraction analysis. Using X-ray photoelectron spectroscopy, cobalt ions are shown to have an oxidation state of 2+, with titanium ions having a tetravalent state of Ti4+. In the as-prepared state, all investigated compounds of Ti1–xCoxO2 are paramagnetic, with the value of paramagnetic susceptibility growing in proportion to cobalt content; with the spin of cobalt ion equal to S = 3/2. Analysis of the electron paramagnetic resonance spectra reveals that doping TiO2 with cobalt (up to 2%) is accompanied by a significant increase in the concentration of F+ centers. Further growth of the cobalt content results in a relatively wide line (nearly 600 Oe) in the spectrum, with a g-factor of about 2.005, demon...

A comprehensive study of the magnetic phase transitions in Tb3Co has been undertaken combining different techniques. Using single crystal neutron diffraction in the paramagnetic state a weak crystal structure distortion from the room temperature orthorhombic structure of the Fe3C type described with the Pnma space group toward structure with lower symmetry has been observed with cooling below 100 K. At 81 K there is a second order phase transition to an antiferromagnetic incommensurate phase with the propagation vector k = (0.155, 0, 0). As derived from thermal diffusivity measurements, the critical exponents for this transition are very close to the 3D-Heisenberg universality class, proving that the magnetic interactions are short-range but with a deviation from perfect isotropy due to crystal field effects. At T2 ≈ 70 K there is another magnetic phase transition to a ferromagnetic state whose character is shown to be weakly first order. The low temperature magnetic state has a non-coplanar ferromagnetic structure with strong ferromagnetic components of Tb magnetic moments along the crystallographic c-axis. The application of an external magnetic field B = 2 T along the c crystallographic axis suppresses the incommensurate antiferromagnetic phase and gives rise to the ferromagnetic phase. The magnetic entropy peak change as well as the refrigerant capacity indicate that Tb3Co is a competitive magnetocaloric material in this temperature range. © 2019 Elsevier Ltd

The report is devoted to an analysis of the structural and magnetic state of the nanocrystalline diluted magnetic semiconductors based on TiO2 doped with Fe and Co atoms. Structural and magnetic characterization of samples was carried out using X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR) spectroscopy, SQUID magnetometry, and the density functional theory (DFT) calculations. Analysis of the experimental data suggests the presence of non-interacting paramagnetic Fe3+ and Co2+ ions in the high-spin state and negative exchange interactions between them. The important conclusions is that the distribution of dopants in the TiO2 matrix, even at low concentrations of 3d-metal dopant (less than one percent), is not random, but the 3d ions localization and dimerization is observed both on the surface and in the nanoparticles core. Thus, in the paper the quantum mechanical model for describing the magnetic properties of TiO2:(Fe, Co) was suggested. The model operates only with two parameters: paramagnetic contribution of non-interacting 3d-ions and dimers having different exchange interactions between 3d magnetic carriers.

We analyze coexistence of antiferromagnetic and ferromagnetic phases in bulk iron-rhodium and its alloys with palladium, Fe50,4Rh49,6, Fe49,7Rh47,4Pd2,9 and Fe48,3Rh46,8Pd4,9, using neutron diffraction, magnetization and scanning Hall probe imaging. Temperature dependencies of the lattice parameters, AFM and FM phase weight fractions, and Fe magnetic moment values were obtained on cooling and heating across the AFM-FM transition. Substantial thermomagnetic hysteresis for the phases’ weight fractions and a relatively narrow one for the unit cell volume has been observed on cooling-heating. A clear dependence of hysteretic behavior on Pd concentration has been traced. Additional direct magnetic measurements of the spatial distribution of the phase transition are acquired using scanning Hall probe microscopy, which reveals the length scale of the phase coexistence and the spatial progression of the transition in the presence of external magnetic field. Also, the magnetic phase diagram has been constructed for a series of Pd-doped FeRh alloys. © 2020 Elsevier B.V. EL acknowledges funding from the UK EPSRC. LFC acknowledges funding from the EPSRC and InnovateUK: Project number: 105541. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This work was partly supported by the state assignment of the Ministry of Science and Higher Education (themes “Flux” No. AAAA-A18-118020190112-8 and “Alloys” № AAAA-A19-119070890020-3).

We present a study of the crystal structure, ionic conductivity and Li migration map in a wide temperature range for the Li2ZrO3 and Li1.8ZrO3-δ samples synthesized by the solid state reaction and soft chemistry methods, respectively. Both samples were found to be Li-deficient at room temperature with the partially vacant Li[1] sites. Thermally activated redistribution of Li+ ions between two lithium sites has been revealed by high temperature neutron diffraction. The redistribution of lithium results in rise of the ionic conductivity and drop of the activation energy observed on the AC conductivity data at the temperatures above 740 K for Li2ZrO3 and 710 K for Li1.8ZrO3-δ. It has been found that more deficient Li1.8ZrO3-δ sample prepared by the soft chemistry method exhibits enhanced ionic conductivity. Three-dimensional lithium migration map composed of the stripe-like migration pathways has been constructed. Most of the elementary channels composing lithium migration map were found to be probabilistic ones, which indicates bottle-necked ionic transport in both compounds.

High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) analysis, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), magnetic methods, and density-functional theory (DFT) calculations were applied for the investigations of Co-doped anatase TiO2 nanoparticles ( ∼ 20 nm). It was found that high-spin Co2+ ions prefer to occupy the interstitial positions in the TiO2 lattice which are the most energetically favourable in compare to the substitutional those. A quantum mechanical model which operates mainly on two types of Co2+ – Co2+ dimers with different negative exchange interactions and the non-interacting paramagnetic Co2+ ions provides a satisfactorily description of magnetic properties for the TiO2:Co system.

Magnetic properties and magnetic structures of layered GdMn2Si2 compound were studied using quasi-single crystal, high magnetic fields up to 520 kOe, and neutron powder diffraction experiment designed for high absorbent systems. It was shown that GdMn2Si2 has strong easy plane type magnetic anisotropy at temperatures TGd

In this paper we report the detailed study of magnetic phase diagrams, low-temperature magnetic structures, and the magnetic field effect on the electrical resistivity of the binary intermetallic compound Tb3Ni. The incommensurate magnetic structure of the spin-density-wave type described with magnetic superspace group P1121/a1′(ab0)0ss and propagation vector kIC=0.506,0.299,0 was found to emerge just below Néel temperature TN=61 K. Further cooling below 58 K results in the appearance of multicomponent magnetic states: (i) a combination of k1=12,12,0 and kIC in the temperature range 51

Powder neutron diffraction and specific heat measurements have been employed to study the evolution of an antiferromagnetic (AFM) structure in the intercalated Fe0.5TiS2−ySey compounds with S–Se substitution and under application of a magnetic field. In Fe0.5TiS2 ( y = 0 ), the magnetic structure just below T N ≃ 140 K is incommensurate while it becomes commensurate with further cooling below T t ≃ 125 K. The presence of two magnetic phase transitions at T t and T N in Fe0.5TiS2 is confirmed by specific heat measurements. The field-induced AFM–FM transitions occurring in Fe0.5TiS2 within temperature interval T t T T N and below T t are evidenced by neutron diffraction measurements under application of a magnetic field. Unlike Fe0.5TiS2 having a quadruplicated AFM structure, the compounds with the Se concentrations y > 0.5 are observed to exhibit an AFM structure with the doubled magnetic unit cell along a and c crystallographic directions of the monoclinic crystal lattice ( I 12 / m 1 space group). In the transition region around the critical Se concentration y c ≈ 0.5 , the magnetic structure of Fe0.5TiS2−ySey is found to be incommensurate. The appearance of the AFM order with decreasing temperature in Fe0.5TiS2−ySey is accompanied by anisotropic deformations of the crystal lattice. At low temperatures, the Fe magnetic moments in all Fe0.5TiS2−ySey form an angle 14–16° to the c crystallographic direction, which can be ascribed to the crystal field effects and spin-orbit couplings.

Rapid quenching and ball milling have been used to modify the magnetic state and magnetocaloric properties of the intermetallic compound Gd3Ni. The melt-spun and ball-milled Gd3Ni samples are found to exhibit a soft ferromagnetic-like behavior below 120 K, whereas in the crystalline state, the Gd3Ni compound is an antiferromagnet with a Neel temperature of about 99 K. The reduced value of the saturation magnetization observed in amorphous Gd3Ni samples is ascribed to the appearance of a magnetic moment on Ni atoms. After amorphization, the Gd3Ni samples exhibit substantially improved magnetocaloric properties in a low field region in comparison with crystalline Gd3Ni.

A study on the magnetocaloric properties of a Tb3Ni single crystal (which crystallizes in the orthorhombic Pnma space group) has been undertaken and combined with the study of the character and critical behavior of its magnetic transitions. It presents two important magnetocaloric effects in the temperature range 3–90 K due to the richness and variety of its temperature and magnetic field induced phase transitions. There is a conventional (direct) magnetocaloric effect with a maximum at 65 K and very competitive properties: | Δ S M p k | = 16.6 J/kgK, RCFWHM = 432 J/kg, with a 50 K span, for μ0ΔH = 5 T, which is due to the transition from a magnetically ordered state to the paramagnetic (PM) state with a combined antiferromagnetic to ferromagnetic (AFM-FM) metamagnetic transition. Besides, it also presents an inverse magnetocaloric effect at very low temperature for which the presence of metamagnetic transitions between AFM and FM states is responsible ( Δ S M p k =19.9 J/kgK, RCFWHM = 245 J/kg, with a 15 K span, for μ0ΔH = 5 T). At low field (

A study of the magnetic susceptibility of electron systems of hybridized states of iron, cobalt, and nickel impurities in mercury selenide crystals at low temperatures, in connection with newly discovered evidence of spontaneous spin polarization in the anomalous Hall effect, at room temperature. It is shown that in the measured paramagnetic susceptibility of electrons in hybridized states, there exists a temperature-independent portion, and that there is enough justification to identify it using spontaneous polarization. The other portion demonstrates the Curie law with decreasing temperature, and corresponds to contributions from nonpolarized electrons. Based on findings relating to the magnetization of the examined impurity systems, we identify a part of the spontaneously polarized electron density in the localized component of hybridized states. We give quantitative estimates of the aforementioned portions of each impurity.

Elastic and inelastic neutron scattering and magnetization measurements have been used to study peculiarities of the magnetic state in R{sub 3}T compounds (R=Gd, Er, Tb; T=Ni, Co) below and above magnetic ordering temperatures. A pronounced non-Brillouin shape of the magnetization curves observed in the antiferromagnetic compounds Gd{sub 3}Ni and Tb{sub 3}Ni above their magnetic ordering temperatures together with earlier reported data about the retention of the magnetic contribution to the total specific heat of Gd{sub 3}T and anomalous behavior of the electrical resistivity above magnetic ordering temperatures are ascribed to the existence of short-range magnetic correlations in the wide temperature range in the paramagnetic state. The persistence of short-range magnetic order up to temperatures greater than 5-6 times the Neel temperature has been revealed by powder neutron diffraction measurements performed for Tb{sub 3}Ni and Tb{sub 3}Co. On the other hand, results from inelastic neutron scattering show that the low temperature magnetic excitations are strongly suppressed in both Tb{sub 3}Co and Er{sub 3}Co. It is suggested that the extended short-range magnetic correlations, which turn out to be an inherent feature of R{sub 3}T type compounds, are due to the layered crystal structure and to the difference between geometrically frustrated intra-layer exchangemore » interactions and inter-layer exchange.« less

Temperature dependent micro-structural and magnetic properties of CrO2 nanorods have been studied by neutron diffraction from 3.5 K to 450 K. Rietveld analysis considering the anisotropic shape of nanorods suggested that each CrO2 nanorod probably consisted of a few microscopically oriented grains. Around the ferromagnetic transition temperature (∼395K), a dominant lattice distortion in the tetragonal phase was not a change along the c axis, but a contraction along the ab axes perpendicular to the lengthwise direction of the nanorods, which was caused by an apical bond contraction in CrO6 octahedra. The obtained structural and magnetic data of CrO2 nanorods were compared with the temperature dependent resistivity of the epitaxial CrO2/TiO2 film, and strong couplings between structural, magnetic, and electric properties in the half-metallic ferromagnet CrO2 were observed.

The Tb0.1Tm0.9Co2 compound is investigated using neutron diffraction. It is shown that this compound undergoes an irreversible band metamagnetic transition induced by an external magnetic field. The magnetization of the Co sublattice increases from 0.2 to 0.6 μB. The critical field strength is approximately equal to 1 T at temperatures of 1.8 and 4.0 K. As the temperature increases, the effect of the magnetic field on the magnetic state of the sample weakens and, at 25 K, no noticeable changes are observed in an external field of 0.75 T. The metamagnetic transition at 1.8 K is accompanied by the disappearance of rhombohedral distortions and brings about a lattice expansion by approximately 1%.

A comparative study of four series of pyrrhotite-type chalcogenide compounds Fe(7-y)M(y)X(8) (X = S, Se) with substitution of Ti or Co for iron has been performed by means of x-ray and neutron powder diffraction, and by magnetization measurements. In Fe(7-y)M(y)X(8) compounds having a ferrimagnetic order at y = 0, the substitution of either Ti or Co for iron is observed to result in a monotonous decrease of the magnetic ordering temperature, while the resultant magnetization shows a non-monotonous behavior with a minimum around y = 1.0-1.5 in all the Fe(7-y)M(y)X(8) families except Fe(7-y)Co(y)Se(8). Suppression of a magnetically ordered state with substitutions in Fe(7-y)M(y)X(8) is ascribed to nearly zero values of Ti and Co magnetic moments, while the non-monotonous changes of the resultant magnetization are explained by the compensation of the sublattice magnetizations due to the non-random substitutions in alternating metallic layers. The difference in the cation partitioning observed in Fe(7-y)Ti(y)X(8) and Fe(7-y)Co(y)X(8) is attributed to the difference in the spatial extension of Ti and Co 3d orbitals. High coercive field values (20-24 kOe) observed at low temperatures in the Ti-containing compounds Fe(7-y)Ti(y)X(8) with y ⩾ 3 are suggested to result from the enhancement of Fe orbital moment due to the Ti for Fe substitution.

The Tm1−x TbxCo2 (0 ≤ x ≤ 1) system was studied by measuring the magnetic susceptibility, electrical resistance, and neutron diffraction. In the compounds with 0 < x ≤ 0.15, an inhomogeneous magnetic state characterized by the existence of large regions (up to 100 A in size) with short-range ferrimagnetic order was found to occur. The maximum of the residual electrical resistance observed in the compound with x = 0.1 at the magnetic ordering temperature was established to be due to the scattering of conduction electrons by localized spin fluctuations associated with f-d exchange fluctuations caused by the substitution of terbium for thulium. The increase in the terbium concentration to x ≥ 0.15 leads to a sharp increase in the Co sublattice magnetization and the establishment of a long-range ferromagnetic order, which indicates a concentration metamagnetic transition in the band subsystem.

The title compound is prepared by solid state reaction of TiI4, S, and highly pure Fe (evacuated quartz tube; 1.

The magnetic state of the Tb3Co compound with orthorhombic structure has been investigated by measuring the magnetization in static and pulsed magnetic fields and using neutron diffraction analysis. It is shown that the antiferromagnetic modulated structure, arising in this material at T < T N = 82 K, passes upon cooling below T t ≈ 72 K to an incommensurate magnetic structure with a ferromagnetic component along the c axis.

AC- and DC-susceptibility, high-field magnetization and neutron diffraction measurements have been performed in order to study the magnetic state of R5Pd2 (R = Ho, Tb) compounds. The results show that both compounds undergo cluster-glass freezing upon cooling below Tf. According to the neutron diffraction a long-range magnetic order is absent down to 2 K and magnetic clusters with short-range incommensurate antiferromagnetic correlations exist not only below Tf but also in a wide temperature range above the freezing temperature (at least up to 2Tf). A complex cluster-glass magnetic state existing in Ho5Pd2 and Tb5Pd2 down to low temperatures results in rather complicated magnetization behavior in DC and AC magnetic fields. Such an unusual magnetic state in compounds with a high rare-earth concentration may be associated with the layered type of their crystal structure and with substantial atomic disorder, which results in frustrations in the magnetic subsystem.

Measurements of the magnetic susceptibility, magnetization, electrical resistivity and neutron diffraction have been performed for the compound Fe(0.5)TiS(2) in which Fe atoms are intercalated between S-Ti-S tri-layers. It has been shown that this compound with a monoclinic crystal structure exhibits an antiferromagnetic (AF) ground state below the Neel temperature T(N) ≈ 140 K. Small deviations from the stoichiometry and some disordering effects caused by the additional low-temperature heat treatment do not affect substantially the AF state in Fe(0.5)TiS(2). According to neutron diffraction data the magnetic structure at 2 K is described by the propagation vector k = (1/4,0,1/4). The Fe magnetic moments with a value of (2.9 ± 0.1) μ(B) are directed at an angle of (78.5 ± 1.8)° to the layers. Application of the magnetic field at T < T(N) induces a metamagnetic phase transition to the ferromagnetic (F) state, which is accompanied by the large magnetoresistance effect (|Δρ/ρ| up to 27%). Below 100 K, the field-induced AF-F transition is found to be irreversible, as evidenced by magnetoresistance and neutron diffraction measurements. The magnetization reversal in the metastable F state is accompanied at low temperatures by substantial hysteresis (ΔH ~ 100 kOe) which is associated with the Ising character of Fe ions.

The transition metal sulfide Fe4Ti3S8 with 7:8 composition has been synthesized and studied by using X-ray diffraction, magnetization and electrical resistivity measurements. This compound exhibits a monoclinic crystal lattice (space group I12/m1). The substitution of Ti for Fe in Fe7S8 is found to result in a lowering of the Curie temperature (TC ≈ 205 K), in a larger value of the coercive field (Hc ∼ 9 kOe at low temperatures) and in a substantial growth of the resultant magnetic moment per formula unit (μFU) in comparison with Fe7S8. An enhanced value of μFU is attributed to the preferential substitution of Ti in alternating cation layers. From the paramagnetic susceptibility measured within temperature interval (250-350) K, a reduced value of the effective moment per iron (μFe ∼ 2.4μB) was determined. The electrical resistivity of Fe4Ti3S8 shows a non-metallic behavior and is affected by magnetic ordering. © 2013 Elsevier Masson SAS. All rights reserved.

The crystal structure and magnetic properties of ErFe 2D 3.1 have been studied by means of magnetic measurements and neutron powder diffraction in a wide temperature range from the highest temperature T = 450 K down to the lowest one T = 12 K. The crystal structure of ErFe 2D 3.1 is found to be strongly modified by temperature: the high-temperature cubic structure decomposes to the deuterium-deficient cubic and deuterium-rich distorted phases which coexist in a wide temperature range below 400 K and exhibit successive structural transitions. The neutron powder diffraction patterns analysis revealed ordering of deuterium atoms over preferential A 2B 2 interstitial sites upon cooling. Below the Curie temperature ErFe 2D 3.1 is a ferrimagnet. Two separate magnetic ordering temperatures for Er and Fe magnetic sublattices were observed. A large magnetic anisotropy has been found in ErFe 2D 3.1 at low temperature. © 2012 Elsevier B.V. All rights reserved.

The structure of the title compounds is determined by X-ray and high-resolution neutron powder diffraction at 450 K.

The measurements of the magnetization in high steady and pulsed fields together with neutron diffraction measurements on a powder sample and on a single crystal have been performed to study the magnetic state of the Tb3Co compound. It has been shown that the modulated antiferromagnetic structure which exists in Tb3Co below TN = 82 K transforms to the incommensurate magnetic structure with a strong ferromagnetic component along the c-axis with further cooling below the critical temperature Tt≈72 K. The phase transition from the high-temperature to the low-temperature magnetic state at Tt is of first order. The incommensurability of the low-temperature magnetic structure of Tb3Co is attributed to the non-Kramers character of the Tb3+ ion in combination with competition between the indirect exchange interaction and the low-symmetry crystal electric field.

This paper presents a catalog of algorithms for automatically processing aerospace pictures, including more than fifty items, systematized according to the following topics: structural comparison of images, comparison of images on the basis of Fourier invariants, alignment of images in a single coordinate system, detection of changes of the terrain on the basis of aerospace pictures, reconstruction and improvement of images, processing of information extracted from radar pictures, recognition of objects of specified classes on aerospace pictures, measurement of the elevation of objects from their aerospace pictures, searching for images in databases, geocoding of aerospace pictures, compression of images, development of camouflaging materials, and auxiliary algorithms for computing the attributes of images. The input and output data and the operating principles are briefly described for the presented algorithms.