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In ternary nitrides, the Ga0.9Fe3.1N sample has ultimately been prepared through solid‐gas preparation for the gallium‐richest phase GaFe3N. The substitution of gallium atoms for iron atoms weakens the saturation magnetization of ferromagnetic γʹ‐Fe4N and induces the transmission from ferromagnetism to antiferromagnetism. A new magnetic behavior, defined as the spin glassy magnetic state, has been observed in the temperature‐dependent magnetic performance measurement process for Ga0.9Fe3.1N. The magnetic competition between ferromagnetic and antiferromagnetic Fe–Fe bonds will lead to the spin frustration of the magnetic system. And even the positional disorders caused by substitution, will all be responsible for the spin glassy behavior in Ga0.9Fe3.1N. [ABSTRACT FROM AUTHOR]

A series of Zn-substituted CoCr2O4 spinel powders were prepared by solid-state reaction method. On this basis, the crystal structure and magnetic properties of CoCr2O4 powders were studied. By comparing the X-ray diffraction (XRD) pattern with the CoCr2O4 spinel standard card, it can be seen that the position of the main peak changes with the increase of zinc content and moves to the direction of higher Angle. In other words, with the increase of Zn displacement, the average grain size and lattice parameters also change. The crystal structure and magnetic properties of the materials were studied using the following instruments: scanning electron microscope (SEM) image can clearly see the uniform grain distribution. The chemical valence states of zinc, cobalt, and chromium ions fitted by X-ray photoelectron spectroscopy (XPS) are consistent with those reported in previous literature. The formation of spinel chromite can be clearly seen in the Fourier transformer infrared (FTIR) image. The hysteresis loop at 5 K shows that the saturation magnetization and coercivity decrease with the increase of Zn2+ content. At room temperature (300 K), the hysteresis loops of the five samples are linear. When x = 0.1 and 0.3, ZFC curve shows negative magnetization behavior across the temperature axis. The paramagnetic behavior also confirmed the pure spinel phase shown in the powder XRD profile. [ABSTRACT FROM AUTHOR]

A series of M‐type Ba−Sr hexaferrites of composition Ba0.20Sr0.80‐xSmxFe12‐y(Cr0.5Al0.5)yO19 (x=0.00–0.40; y=0.00–0.32) were prepared by solid‐state reaction route. XRD patterns reveals that there is a single magnetoplumbite phase in the hexaferrites with the substitutiom of Sm (0.00≤x≤0.20) and CrAl (0.00≤y≤0.16) contents, while for the hexaferrites containing Sm (x≥0.30) and CrAl (y≥0.24), impurity phase is detected in the structure. The remanence (Br) decreases with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). With the increase of substitution contents, the intrinsic coercivity (Hcj) increases, while the magnetic induction coercivity (Hcb) first increases, and then decreases. Br has a linear decreasing behavior with increasing temperature from 20 °C to 170 °C. Hcj raises linearly with increasing temperature from 20 °C to 170 °C. The average temperature coefficient of Br (αBr) basically remains constant with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). The average temperature coefficient of Hcj (αHcj) decreases with increasing substitution content of Sm (0.00≤x≤0.40) and CrAl (0.00≤y≤0.32). The electrical resitivity (ρ) decreases with increasing substitution content of Sm‐CrAl. [ABSTRACT FROM AUTHOR]

Rare earth elements possessing a diverse range of optical, electrical, and magnetic properties has attracted more attention. In the present work, GdClWO 4 compound with monoclinic structure was prepared, the structure, magnetism and magnetocaloric effect (MCE) were investigated. The magnetic phase transition temperature (T N), magnetic ground state and maximum magnetic entropy change ( − Δ S M max) were derived from magnetization measurements. Both first principles calculation and experimental results suggest that the compound displays antiferromagnetic (AFM) interactions, with a magnetic transition occurring at 0.6 K, shifting from a paramagnetic (PM) state to an AFM state. The − Δ S M max is up to 35.2 J kg−1 K−1 (205.9 mJ cm−3 K−1) for GdClWO 4 at T = 1.3 K under a magnetic field change of 0–50 kOe. In particular, the volumetric magnetic entropy change still remains 83.1 mJ cm−3 K−1 at 0.5 K and μ 0 Δ H = 20 kOe, which is almost twice as much as that of commercial refrigerant Gd 3 Ga 5 O 12 (GGG) under μ 0 Δ H = 20 kOe, establishing GdClWO 4 compound as a potential candidate for cryogenic refrigeration applications. [ABSTRACT FROM AUTHOR]

In this study, double perovskites of Gd 2 FeMnO 6 (GFMO) are successfully prepared using the solid-state reaction method. X-ray diffraction results indicate that GFMO has an orthogonal structure (space group Pnma). Moreover, X-ray photoelectron spectroscopy results show mixed-valence states of 3d transition ions. A further analysis of thermomagnetic data suggests that, in addition to the canted antiferromagnetism and spin reorientation, there is also a Griffiths phase with an antiferromagnetic ground state caused by ferromagnetic short-range interactions and confirmed by electron spin resonance analysis. Antisite-disordered B-site ions give rise to different short-range magnetic orders, which disrupt the long-range ferromagnetic order of Fe–O–Mn, leading to the formation of a short-range ferromagnetic order. Furthermore, with magnetocaloric magnitudes of 17.0 J kg−1 K−1 for 0–50 kOe, GFMO polycrystalline is a promising candidate for magnetic refrigerants in the ultra-low temperature range. Finally, the change in magnetic entropy due to spin reorientation at room temperature (285K) has potential applications in thermostatic water bath switches. [ABSTRACT FROM AUTHOR]

The semiconductor-type EuMnSb 2 single crystal with an orthorhombic structure (space group Pnma , No.62) was synthesized using the Sn-flux method, and its physical properties were systematically investigated by magnetization, specific heat, and resistivity measurements. The magnetic and specific heat features reveal two successive antiferromagnetic (AFM) transitions exist separately at T N 1 ∼ 21 K and T N 2 ∼ 9 K, which have different responses to external magnetic field, and magnetic anisotropy is enhanced as the temperature is below T N 1. When the magnetic field is about 1.7 T and parallels the a -axis of the EuMnSb 2 crystal, a spin-flop transition of the AFM order appears. Electronic transport measurements show that the single crystal of EuMnSb 2 manifests semiconductor characteristic and magnetic field-induced semiconductor-to-metal transitions. In addition, we observe a colossal negative magnetoresistance for both in-plane and out-of-plane resistivity and two-fold period anisotropic magnetoresistance. Combining magnetic susceptibility, specific heat capacity and resistivity properties, we present a phase diagram which can be divided into AFM semiconductor, paramagnetic semiconductor and paramagnetic metal. These unique properties indicate that EuMnSb 2 can provide a platform for investigating the interplay between magnetic order, and charge transport. • Two successive AFM transitions of Eu moments were revealed by magnetic susceptibility and specific heat measurements. • Both in-plane and out-of-plane resistivity exhibit semiconductor-to-metal transition and colossal negative magnetoresistance. • Angle-dependent out-of-plane resistivity exhibits different behavior of anisotropic magnetoresistance above and below T N. • The magnetic phase diagrams help to understand the complex properties of semiconductor EuMnSb 2 crystals. [ABSTRACT FROM AUTHOR]

Herein we systematically investigated the alloying effects on structural, magnetic, and electrical/thermal transport properties in MAX-phase Cr 2− x M x GeC ( M = Ti, V, Mn, Fe, and Mo). The alloying of M with the larger covalent radius than that of Cr increases lattice constants ( a and c ) as well as unit cell volume (V) of Cr 2− x M x GeC, and vice versa. However, the c / a ratio monotonously decreases with increasing alloying level x , which is due to a larger change of a than that of c . The Pauli paramagnetic ground state of Cr 2 GeC is confirmed by magnetic measurements and low-temperature specific heat analysis. Interestingly, ferromagnetism can be introduced in Cr 2− x M x GeC by doping magnetic elements (Mn and Fe) and non-magnetic elements (Ti and Mo), which may be due to a reconstruction of the Fermi surface caused by chemical doping. All our samples show a metal-like electrical transport behavior, and the residual resistivity ratio decreases with increasing alloying concentration, which are mainly attributed to the disorders induced by alloying. The change of electron specific heat coefficient is consistent with the change of density state of Fermi surface in Cr 2− x M x GeC. In addition, solid-solution scattering is the dominant factor for the behavior of thermal conductivity k ( T ) in Cr 2− x V x GeC, while enhanced phonon scattering induced by alloying is the decisive factor for the change of k ( T ) in Cr 2− x Mo x GeC. The positive Seebeck coefficient of Cr 2− x V x GeC and Cr 2− x Mo x GeC may be close related to the decrease of structural anisotropy. [ABSTRACT FROM AUTHOR]