Cr Moments Research Articles

Layer-By-Layer Magnetic Ordering via Idle Spins and the Optical Signature of Jahn-Teller Cr2+ Ions in Sr2Cr(PO4)2.

Blue/turquoise crystals of Sr2CrII(PO4)2 with prismatic shape and edge-length of up to 1 mm were obtained by a vapor-phase moderated solid-state reaction at 1273 K in sealed silica tubes. Its crystal structure was solved and refined from a triply twinned ("trilling") crystal [Pbca (no. 61), Z = 12, a = 10.7064(6) Å, b = 9.2730(5) Å, c = 21.2720(7) Å, R1 = 0.038]. Sr2Cr(PO4)2 belongs to the small family of inorganic solids containing divalent chromium, where the rare Cr2+ ions are stabilized by the inductive effect of the phosphate groups. As expected from its d4 (S = 2) electronic configuration, the Jahn-Teller effect (JT) is prominent, leading for the two independent Cr2+ ions to square-pyramidal Cr(1)O4+1 and square-planar Cr(2)O4 coordination within a 3D chromium phosphate network [CrII2(PO4)4]8. Topologically, the Cr(1) and Cr(2) cations are arranged in separate alternating layers stacked along the c axis. In their respective layers, Cr(1) shows a gapped 2D topology and only weak interaction with the adjacent Cr(2) layers. However, below TN1 ∼11.3 K, Cr(1) orders antiferromagnetically into a noncollinear structure, leaving nearly paramagnetic Cr(2) idle spins, strongly frustrated by the Cr(1) moments of the next layers. On further cooling, below TN2 ∼3.6 K, the ordering of Cr(2) occurs via an additional magnetic irreducible representation, which splits the Cr(1) into Cr(1)a and Cr(1)b orbits, thus lifting the frustration on Cr(2). The corresponding P21ca.29.99 magnetic space group forces a crystal symmetry lowering, plausibly signed by a change of the magnetostrictive coefficient from positive to negative below TN2. The optical transitions observed for the JT d4 ions are in good agreement with our crystal picture from the DFT calculations. A detailed analysis within the angular overlap model explains the surprisingly different d orbital splitting by the ligand field for the chromophores Cr(1)O4+1 and Cr(2)O4.

Giant exchange splitting in the electronic structure of A-type 2D antiferromagnet CrSBr

We present the evolution of the electronic structure of CrSBr from its antiferromagnetic ground state to the paramagnetic phase above TN = 132 K, in both experiment and theory. Low-temperature angle-resolved photoemission spectroscopy (ARPES) results are obtained using a novel method to overcome sample charging issues, revealing quasi-2D valence bands in the ground state. The results are very well reproduced by our QSGŴ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm{QSG}}\\hat{{\\rm{W}}}$$\\end{document} calculations, which further identify certain bands at the X points to be exchange-split pairs of states with mainly Br and S character. By tracing band positions as a function of temperature, we show the splitting disappears above TN. The energy splitting is interpreted as an effective exchange splitting in individual layers in which the Cr moments all align, within the so-called A-type antiferromagnetic arrangement. Our results lay firm foundations for the interpretation of the many other intriguing physical and optical properties of CrSBr.

The B-site ordering in RFe0.5Cr0.5O3 ceramics and its effect on magnetic properties

Abstract To insight into the B-site ordering in RFe0.5Cr0.5O3 ceramics, a series of RFe0.5Cr0.5O3 ceramics (R = La, Y, Lu) were synthesized by the sol–gel method, and the structural and magnetic properties were systemically investigated. By using the Rietveld refinement of all samples, it is found that the structural distortion is increased as the R ionic radius decreases, leading to the weakened interactions between Fe/Cr ions. Moreover, the Fe and Cr are arranged in disorder in LaFe0.5Cr0.5O3, but partially ordered in YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3, showing an increasing trend of the proportion of ordered domains with the decrease of R ionic radius. Through fitting the temperature-dependent magnetizations, it is identified that the magnetization reversal (MR) in disorder LaFe0.5Cr0.5O3 is resulted from the competition between the moments of Cr and Fe sublattices. In the partially ordered YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3 ceramics, because of the presence of Fe–O–Cr networks in the ordered domains whose moment is antiparallel to that of Fe–O–Fe and Cr–O–Cr in the disordered domains, the compensation temperature T comp of MR is increased by nearly 50 K. These results suggest that the changing of R-site ions could be used very effectively to modify the Fe–O–Cr ordering, apart from the structural distortion, which has a direct effect on the magnetic exchange interactions in RFe0.5Cr0.5O3 ceramics. Then at values of composition where ordered domains are expected to be larger in number as compared to disordered domains and with a weaker structural distortion, one can expect a higher transition temperature T comp, providing a different view for adjustment of the magnetic properties of RFe0.5Cr0.5O3 ceramics for practical applications.

Long-Range Influence of Cr on the Stacking Fault Energy of Cr-Containing Concentrated Solid-Solution Alloys

Single-phase concentrated solid-solution alloys (CSAs) have exhibited excellent mechanical and radiation tolerance properties, making them potential candidate materials for nuclear applications. These excellent properties are closely related to dislocation movements, which depend on the stacking fault energies (SFEs). In CSAs, SFEs show large fluctuations due to variations in the local atomic environments in the vicinity of the stacking faults. In this work, first-principle calculations were performed to investigate the origin of the fluctuations in the SFEs of the widely studied CSA, NiCoCr, which show a very wide distribution from about −200 mJ/m2 to 60 mJ/m2. Compared to the common understanding that only atoms in close proximity to the stacking fault influence the SFEs in pure metals and dilute alloys, charge redistribution can be observed in several nearby planes of the stacking fault in NiCoCr, indicating that atoms several atomic layers away from stacking fault also contribute to the SFEs. Our analysis shows that Cr plays a major role in the large fluctuation in the SFEs of NiCoCr based on both electronic and magnetic responses. The flexible electronic structure of Cr facilitates easier charge transfer with Cr in several nearby atomic planes near the stacking fault, leading to significant changes in the d-electron number, orbital occupation number, and magnetic moments of Cr.

High valley-degeneracy electron gas at double perovskite - strontium titanate interface

Emergent phenomena such as two-dimensional electron gas (2DEG) and interfacial superconductivity and ferromagnetism are generally built on the interface between insulating oxide thin films and substrates, e.g., LaAlO3/SrTiO3, where the 2D profiles of these electronic states are precisely confined at the interface of two insulators. Herein we report a high-mobility electron gas state with unusual symmetry at the interface of the Sr2CrMoO6/SrTiO3 (110) heterostructures, the fermiology of which follows the cubic crystallographic symmetry rather than the two-dimensional interface itself, resulting in the identical Shubnikov-de Haas oscillations with applied magnetic field along all the twelve equivalent [110] crystallographic directions of SrTiO3, distinctly different from the 2D nature of the electron gas reported previously. Neutron diffraction verifies the predicted ferrimagnetic ordering between Cr and Mo moments. This, together with the magnetic hysteresis loops and negative magnetoresistance in low-field region, suggests possible spin polarization of itinerant electrons. Therefore, a quasi-3D profile, high mobility (up to 104 cm2 V−1 s−1) and possibly spin polarized electronic state is observed in the double-perovskite-based oxide heterostructures. This finding of the electronic properties in Sr2CrMoO6/SrTiO3 (110) heterostructure expands the knowledge of interfacial physics, as well as shines light on oxide-based electronics and spintronics research.

Magnetism of single-doped paramagnetic tin clusters studied using temperature-dependent Stern-Gerlach experiments with enhanced sensitivity: impact of the diamagnetic ligand field and paramagnetic dopant.

In this work, the magnetic properties of tetrel clusters SnNTM, which are singly doped with transition metals (TM), are investigated. On the one hand, the number of tetrel atoms (N = 11, 12, 14 and 17 with TM = Mn) is varied; on the other hand, different transition metals (N = 14, TM = Cr, Mn, Fe) are studied. Magnetic deflection experiments under cryogenic conditions show that the variation of the number of tetrel atoms strongly changes the magnetic properties of the Mn-doped clusters. It is observed that Sn12Mn, Sn11Mn and Sn14Mn partially show super-atomic behaviour, while spin relaxation occurs in Sn17Mn. Magnetic deflection experiments at higher nozzle temperatures were carried out for the first time enhanced by a second parallel-aligned Stern-Gerlach magnet to achieve larger deflections. The resulting temperature-dependent one-sided deflections are quantitatively analysed using Curie's law and show that Sn17Mn possesses the highest magnetic moment of these clusters, followed by Sn12Mn and Sn11Mn. Sn14Mn shows the lowest magnetic moment. The replacement of Mn by Cr in Sn14Mn leads to a diamagnetic singlet, i.e., the magnetic moment of Cr in Sn14Cr is completely quenched. The replacement of Mn by Fe in turn leads to a paramagnetic species, whereby Sn14Fe is most likely present as a triplet. On this basis, the geometrical and electronic structures are analysed using quantum chemical calculations, indicating an arachno-type structure for Sn14Cr, Sn14Mn and Sn14Fe, which has already been predicted in the literature for Si14Cr. This is experimentally confirmed by deflection of molecular beams with an electric field under cryogenic conditions, suggesting that the arachno-type geometry is crucial for the overall stability of the transition-metal-doped tetrel clusters Sn14TM with TM = Cr, Mn, Fe.

Direct observation of antiferromagnetic domains and field-induced reversal in Pt/Cr2O3/Pt epitaxial trilayers

Antiferromagnet does not show the net magnetization, whereas the finite uncompensated moment can residue at the surface. On the surface of the magnetoelectric antiferromagnet, the finite boundary magnetization can acquire the magnetic response. In this paper, we address the magnetic response of the boundary magnetization in the Pt/magnetoelectric Cr2O3/Pt epitaxial trilayer based on the anomalous Hall effect (AHE) and the soft x-ray magnetic circular dichroism (XMCD). Decreasing the Cr2O3 thickness down to 15 nm, the film acquired the magnetic responsiveness, which manifested as the rectangular hysteresis in the magnetic field dependence of the AHE. The sizable XMCD intensity and the rectangular magnetic field dependence of the XMCD intensity revealed that the magnetic response was attributed to the interfacial Cr moment. The detailed investigation of AHE and XMCD revealed that the domain wall motion dominated the reversal process of the boundary magnetization, which was directly visualized by the scanning XMCD microscope.

Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2O4 revealed with high resolution neutron diffraction and SR

The mixed valence Cr3+/Cr4+ compound NaCr2O4, hosts a plethora of unconventional electronic properties. In the present study, muon spin rotation/relaxation (SR) and high-resolution time-of-flight neutron powder diffraction measurements were carried out on high-quality samples to clarify the complex magnetic ground state of this unique material. We identified a commensurate canted antiferromagnetic order (C-AFM) with a canting angle of the Cr spin axial vector equal to , and an estimated Cr moment . Such an unusually large value of is compatible with the existence of high-spin Cr sites created by the presence of an unconventional negative charge transfer state in NaCr2O4. In addition to the C-AFM structure, a novel magnetic supercell was also revealed. Such supercell display an incommensurate (IC)-AFM propagation vector (0 0 ), having a Cr moment . It is suggested that the C-AFM and IC-AFM modulations have two different electronic origins, being due to itinerant and localized contributions to the magnetic moment respectively. Finally, the direct measurement of the magnetic order parameter for the C-AFM structure provided a value of the critical exponent , suggesting a non conventional critical behavior for the magnetic phase transition in NaCr2O4.

Spin Reorientation Transition and Negative Magnetoresistance in Ferromagnetic NdCrSb3 Single Crystals.

High-quality NdCrSb3 single crystals are grown using a Sn-flux method, for electronic transport and magnetic structure study. Ferromagnetic ordering of the Nd3+ and Cr3+ magnetic sublattices are observed at different temperatures and along different crystallographic axes. Due to the Dzyaloshinskii-Moriya interaction between the two magnetic sublattices, the Cr moments rotate from the b axis to the a axis upon cooling, resulting in a spin reorientation (SR) transition. The SR transition is reflected by the temperature-dependent magnetization curves, e.g., the Cr moments rotate from the b axis to the a axis with cooling from 20 to 9 K, leading to a decrease in the b-axis magnetization f and an increase in the a-axis magnetization. Our elastic neutron scattering along the a axis shows decreasing intensity of magnetic (300) peak upon cooling from 20 K, supporting the SR transition. Although the magnetization of two magnetic sublattices favours different crystallographic axes and shows significant anisotropy in magnetic and transport behaviours, their moments are all aligned to the field direction at sufficiently large fields (30 T). Moreover, the magnetic structure within the SR transition region is relatively fragile, which results in negative magnetoresistance by applying magnetic fields along either a or b axis. The metallic NdCrSb3 single crystal with two ferromagnetic sublattices is an ideal system to study the magnetic interactions, as well as their influences on the electronic transport properties.

Tunable Electronic and Magnetic Properties of T-CrTe2 Monolayer by Li Adsorption

Using first-principle calculations, we investigate the electronic and magnetic properties of Li-adsorbed T-CrTe2 monolayer. We demonstrate that Li adsorption turns the electronic properties mainly through electron doping and lattice expansion. As the adsorption concentration increases from 3.7% to 33.3%, the magnetic moment of Cr increases from 2.25 to 2.98μB linearly. More interesting, the T-CrTe2 monolayer becomes ferromagnetic semiconductors with indirect band gaps under the tensile strain. While a tensile strain is applied, a transformation from metal to half-metal has been found. Our work provides an efficient strategy to seek magnetism and produce two-dimensional magnetic semiconductors and half-metals from metals.

Nuclear and magnetic spin structure of the antiferromagnetic triangular lattice compound LiCrTe2 investigated by mu ^+SR, neutron and X-ray diffraction

Two-dimensional (2D) triangular lattice antiferromagnets (2D-TLA) often manifest intriguing physical and technological properties, due to the strong interplay between lattice geometry and electronic properties. The recently synthesized 2-dimensional transition metal dichalcogenide LiCrTe_2, being a 2D-TLA, enriched the range of materials which can present such properties. In this work, muon spin rotation (mu ^+SR) and neutron powder diffraction (NPD) have been utilized to reveal the true magnetic nature and ground state of LiCrTe_2. From high-resolution NPD the magnetic spin order at base-temperature is not, as previously suggested, helical, but rather collinear antiferromagnetic (AFM) with ferromagnetic (FM) spin coupling within the ab-plane and AFM coupling along the c-axis. The value if the ordered magnetic Cr moment is established as mu _{textrm{Cr}}= 2.36~mu _{textrm{B}}. From detailed mu ^+SR measurements we observe an AFM ordering temperature T_{textrm{N}}approx 125 K. This value is remarkably higher than the one previously reported by magnetic bulk measurements. From mu ^+SR we are able to extract the magnetic order parameter, whose critical exponent allows us to categorize LiCrTe_2 in the 3D Heisenberg AFM universality class. Finally, by combining our magnetic studies with high-resolution synchrotron X-ray diffraction (XRD), we find a clear coupling between the nuclear and magnetic spin lattices. This suggests the possibility for a strong magnon–phonon coupling, similar to what has been previously observed in the closely related compound LiCrO_2.

Theoretical antiferromagnetism of ordered face-centered cubic Cr-Ni alloys

Contrary to prior calculations, the Ni-rich ordered structures of the Cr-Ni alloy system are found to be antiferromagnetic under semilocal density-functional theory. The optimization of local magnetic moments significantly increases the driving force for the formation of ${\mathrm{CrNi}}_{2}$, the only experimentally observed intermetallic phase. This structure's ab initio magnetism appears well described by a Heisenberg Hamiltonian with longitudinal spin fluctuations; itinerant Cr moments are induced only by the strength of exchange interactions. The role of magnetism at temperature is less clear and several scenarios are considered based on a review of experimental literature, specifically a failure of the theory, the existence of an overlooked magnetic phase transition, and the coupling of antiferromagnetism to chemical ordering. Implications for related commercial and high-entropy alloys are discussed for each case.

Superconductivity with large upper critical field in noncentrosymmetric Cr-bearing high-entropy alloys

A series of new Cr5+xMo35−xW12Re35Ru13C20 high-entropy alloys (HEAs) have been synthesized and characterized by x-ray diffraction, scanning electron microscopy, electrical resistivity, magnetic susceptibility and specific heat measurements. It is found that the HEAs adopt a noncentrosymmetric cubic β-Mn type structure and exhibit bulk superconductivity for 0 ≤x≤ 9. With increasing x, the cubic lattice parameter decreases from 6.7940(3) Å to 6.7516(3) Å. Meanwhile, the superconducting transition temperature Tc is suppressed from 5.49 K to 3.35 K due to the magnetic pair breaking caused by Cr moments. For all these noncentrosymmetric HEAs, the zero-temperature upper critical field Bc2(0) is comparable to the Pauli paramagnetic limit BP(0) = 1.86Tc. In particular, the Bc2(0)/BP(0) ratio reaches a maximum of ∼1.03 at x = 6, which is among the highest for β-Mn type superconductors.

Electronic, Magnetic, and Optical Properties of Metal Adsorbed g-ZnO Systems

2D ZnO is one of the most attractive materials for potential applications in photocatalysis, gas and light detection, ultraviolet light-emitting diodes, resistive memory, and pressure-sensitive devices. The electronic structures, magnetic properties, and optical properties of M (Li, Na, Mg, Ca, or Ga) and TM (Cr, Co, Cu, Ag, or Au) adsorbed g-ZnO were investigated with density functional theory (DFT). It is found that the band structure, charge density difference, electron spin density, work function, and absorption spectrum of g-ZnO can be tuned by adsorbing M or TM atoms. More specifically, the specific charge transfer occurs between g-ZnO and adsorbed atom, indicating the formation of a covalent bond. The work functions of M adsorbed g-ZnO systems are obviously smaller than that of intrinsic g-ZnO, implying great potential in high-efficiency field emission devices. The Li, Na, Mg, Ca, Ga, Ag, or Au adsorbed g-ZnO systems, the Cr adsorbed g-ZnO system, and the Co or Cu adsorbed g-ZnO systems exhibit non-magnetic semiconductor proprieties, magnetic semiconductor proprieties, and magnetic metal proprieties, respectively. In addition, the magnetic moments of Cr, Co, or Cu adsorbed g-ZnO systems are 4 μ B, 3 μ B, or 1 μ B, respectively, which are mainly derived from adsorbed atoms, suggesting potential applications in nano-scale spintronics devices. Compared with the TM absorbed g-ZnO systems, the M adsorbed g-ZnO systems have more obvious absorption peaks for visible light, particularly for Mg or Ca adsorbed g-ZnO systems. Their absorption peaks appear in the near-infrared region, suggesting great potential in solar photocatalysis. Our work contributes to the design and fabrication of high-efficiency field emission devices, nano-scale spintronics devices, and visible-light responsive photocatalytic materials.

Cr doping-induced ferromagnetism in the spin-glass Cd1−xMnxTe studied by x-ray magnetic circular dichroism

The prototypical diluted magnetic semiconductor Cd1−xMnxTe is a spin glass (x < 0.6) or an antiferromagnet (x > 0.6) but becomes ferromagnetic upon doping with a small amount of Cr atoms. To investigate the origin of the ferromagnetism in Cd1−x−yMnxCryTe, we have studied its element specific magnetic properties by x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). Measured XAS and XMCD spectra indicate that both Cr and Mn atoms are divalent and that the magnetic moments of Cr and Mn are aligned parallel. The magnetization of Mn increases with increasing Cr content, suggesting that ferromagnetic interaction exists between neighboring Mn and Cr ions despite the largely antiferromagnetic interaction between Mn atoms. By analyzing the element-specific magnetization curves, we conclude that Cr doping leads to the formation of ferromagnetic or superparamagnetic clusters consisting of several Cr ions surrounded by a much larger number of Mn ions.

Exchange interactions and spin dynamics in the layered honeycomb ferromagnet CrI3

We derive the microscopic spin Hamiltonian for rhombohedral CrI$_3$ using extensive first-principles density functional theory (DFT) calculations which incorporate spin-orbit coupling and Hubbard U. Our calculations indicate a dominant nearest-neighbor ferromagnetic Heisenberg exchange with weaker further-neighbor Heisenberg terms. In addition, we find a Dzyaloshinskii-Moriya interaction which primarily drives a topological gap in the spin-wave spectrum at the Dirac point, and uncover a non-negligible antiferromagnetic Kitaev coupling between the S=3/2 Cr moments. The out-of-plane magnetic moment is stabilized by weak symmetric bond-dependent terms and a local single-ion anisotropy. Using linear spin wave theory, we find that our exchange parameters are in reasonably good agreement with inelastic neutron scattering (INS) experiments. Employing classical Monte Carlo simulations, we study the magnetic phase transition temperature $T_c$ and its evolution with an applied in-plane magnetic field. We further demonstrate how future high-resolution INS experiments on the magnon dispersion of single crystals in an in-plane magnetic field may be used to quantitatively extract the strength of the antiferromagnetic Kitaev exchange coupling.

Study on FeCr thin film for a spintronic material with negative spin polarization

Negative spin polarization materials generate a spin current whose spin direction is opposite to the magnetization direction. This characteristic is technologically important because it increases the freedom in the design of spintronic devices. In this paper, we studied FeCr from the viewpoints of band structure, atomic magnetic moments, and local atomic arrangement to explore its potentiality as a negative spin polarization material. First-principles calculations on the disordered FeCr alloy predicted a high negative spin polarization, which was attributed to the band matching of the minority spin. We experimentally fabricated Fe1-xCrx thin films in the Cr concentration (x) range from 0.2 to 0.4 by sputter deposition and demonstrated inverse magnetoresistance using current-perpendicular-to-plane giant magnetoresistance (GMR) devices, which provided evidence of negative spin polarization. The spin polarization of Fe0.7Cr0.3 estimated from the GMR device measurements was −0.28 and fell below the calculated value. Synchrotron X-ray magnetic circular dichroism measurements showed a ferrimagnetic configuration of the Fe and Cr magnetic moments. The Fe moment showed a large moment over a wide Cr concentration range, whereas the Cr moment decreased with the Cr concentration, which agreed with the calculation result. Synchrotron Mössbauer spectroscopy measurements indicated the inhomogeneity of the FeCr composition even in the as-deposited state. Fe-rich regions were formed after annealing, reflecting the phase separation nature of the Fe-Cr system. Inhomogeneity was not considered in the calculation and could be the origin of the smaller negative spin polarization observed in the experiment.

Structural and magnetic properties of DyCrO3

In this contribution, the structural and magnetic properties of DyCrO3 are studied, along with the magnetocaloric effect in this compound. The susceptibility as a function of temperature, χ(T), indicates that DyCrO3 has a G-type antiferromagnetic behaviour with weak ferromagnetism below Néel temperature, TNCr, at 147.1 ± 0.1 K, attributed to the ordering of Cr moments. The Dy moments orders antiferromagnetically below the spin reorientation temperature TSR = 4.81 ± 0.04 K. The dependence of magnetization on the applied magnetic field, Mμ0H, shows a behaviour that corresponds to the χ(T) data. Arrott plots reflect the various magnetic orderings with a change in the gradient of the curves. For the first time, the magnetocaloric effect of sol-gel synthesized DyCrO3 is studied having an average particle size 215 ± 3 nm as obtained from transmission electron microscopy (TEM). Large magnetocaloric effects (MCE) are observed in the temperature range of 10 to 80 K for DyCrO3. The compound shows a relatively large magnetic entropy change (ΔSM) of 21 J.Kg−1.K−1 and relative cooling power (RCP) of 498 J.Kg−1 at 7 T and 10 K. Assuming the relations |ΔSmT,H|=a(H)n and RCP=CH1+1δ, with critical exponents n = 1 and δ → ∞ were obtained from the linearization, confirming the weak ferromagnetic behaviour.

Magnetocaloric, electronic, magnetic, optical and thermoelectric properties in antiferromagnetic semiconductor GdCrO3: Monte Carlo simulation and density functional theory

Density functional theory and Monte Carlo simulation are performed on the magnetocaloric, electronic, optical, thermoelectric and magnetic properties of GdCrO3. The density of states diagrams is discussed. The values of the exchange energy calculated between the magnetic configurations Gd and Cr atoms was calculated. The GdCrO3 has semiconductor character and antiferromagnetic behavior. The dielectric function, absorption and reflectivity are also investigated. The thermoelectric response is evaluated by calculating electrical conductivity, thermal conductivity and seebeck coefficient (S) by using BoltzTraP code. The magnetic moment of Cr and Gd are calculated. The Néel temperature has been obtained. The presence of spin reorientation transition is also observed in this system. The maximum magnetic entropy change and relative cooling power are found to be respectively, 2.64 J.K−1.kg−1 and 25 J.kg−1 for h = 5 T.

Magnetic and structural properties of the intermetallic Ce(1−x)LaxCrGe3 series of compounds

The ${\mathrm{Ce}}_{(1\ensuremath{-}x)}{\mathrm{La}}_{x}{\mathrm{CrGe}}_{3}$ $(x=0, 0.19, 0.43, 0.58, \mathrm{and} 1)$ intermetallic compound system has been investigated by magnetization measurements and neutron scattering techniques to determine the effect of La doping on the magnetic ordering and exchange interaction between Cr ions. The structural and magnetic characterization in this series was first verified by x-ray diffraction and bulk magnetization measurements. The samples exhibit the known hexagonal perovskite structure ($P{6}_{3}/\mathrm{mmc}$ space group) and have a single magnetic phase according to magnetization measurements. In this paper, the ferromagnetic ordering temperature for Cr evolves smoothly from a range of 68 K to 77 K for ${\mathrm{CeCrGe}}_{3}$ to a range of 91 K to 96 K for ${\mathrm{LaCrGe}}_{3}$ as La replaces Ce. Magnetization results indicate the formation of domain walls below the transition temperature for all ${\mathrm{Ce}}_{(1\ensuremath{-}x)}{\mathrm{La}}_{x}{\mathrm{CrGe}}_{3}$ systems investigated. Neutron results indicate ordered magnetic Cr moments aligned along the $c$ axis for the $x=1$ ${\mathrm{LaCrGe}}_{3}$ system, as well as for $x=0.19$, 0.43, and 0.58, which contrasts with the $x=0 {\mathrm{CeCrGe}}_{3}$ where the moments order in the ab plane.