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Ions substitution into spinel ferrites has attracted intensive attention on probing novel physical phenomenon as well as developing the potential fields in information technology. Herein, we focus on a series of magnetic behaviors and thermal stability of Mg(Ga2−xFex)O4 substitution system. The magnetic properties and microstructure of MgGa2O4 spinel ferrites doped with Fe ions at the Ga site have been prepared and systematically investigated in this work. Accordingly, some specific experimental results and conclusions are obtained based on the characterization of structure and magnetic properties. The continuously increasing lattice constants for doping samples and considerable Rietveld fitting results manifest the high quality of the prepared sample. Furthermore, the magnetization and magnetic transition temperature are gradually improved with the increase of Fe-doping concentration. Specifically, the saturation magnetization Ms increased from 5.24 to 35.09 emu/g upon substituting. Based on the Fe substitution, a well preservation of soft magnetic behavior sustains with strengthened Ms, and also inducing some competing magnetic frustration, namely, spin glass (SG). Our discovery paves the pathway for fundamental research in enhancing magnetization and magnetic coupling of spinel ferrites, as well as developing the potential application in low-temperature chip inductors. [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]

Bifunctional oxygen reduction/oxidation reaction (ORR/OER) electrocatalysts derived from biomass are one of the most valuable materials in terms of sustainability, ecological economy and industrial manufacturing, and are emerging as a desired alternative to the commercial Pt/C and IrO2 catalysts. This work demonstrates the processing of agricultural cornstalk waste of cornstalks into stable bifunctional ORR/OER catalysts with high‐performance by a simple and cost‐effective strategy. Rich hydrophilic active groups (e.g., hydroxyl groups) in the hierarchical porous structures of the native cornstalks enable the sufficient facile combination with transition metals (e.g., Co, Fe, Zn) and heteroatoms (e.g., B, N) from soluble Co(NO3)2, ZnCl2, H3BO3, NH4Cl in a hydrothermal reaction. The pyrolytic evaporation of Zn2+ in a high‐temperature carbonization process facilitates the generation of abundant micropores and mesopores to increase specific surface areas (941.44 m2 g−1) and also hinders aggregation between neighboring transition metals. The synergistic effects of N, B, Fe and Co doping in hierarchical porous biochar‐structures contributes to outstanding bifunctional ORR/OER activities and working stabilities, outperforming commercial Pt/C and IrO2 catalysts. Computational results further verify the valuable synergistic contributions based on density‐functional theory (DFT). This approach opens up a new possibility for the fabrication of bifunctional biochar‐based ORR/OER catalysts from artificial engineering and green processing for sustainable agricultural wastes. [ABSTRACT FROM AUTHOR]

The single phase of the spinel ferrite MgGaFeO4 is successfully prepared by the high‐temperature solid‐state reaction. The crystal structure, cation distribution, valence state, and magnetic properties are systematically investigated through various techniques in this work. From the analysis of X‐ray diffraction, the face‐centered cubic structure with the space group Fd3m for the single‐phase sample is obtained. The magnetic hysteresis loops M(H) shows a typical magnetic hysteresis behavior at 5 K, while an obvious paramagnetic behavior can be observed at room temperature. The characteristics of magnetic properties suggest that the intrinsic ferromagnetic (FM) interaction and magnetic frustration are cooperated in the system. The specific divergence and irreversibility in the temperature‐dependent magnetization curves M(T) indicate a typical spin‐glass (SG) behavior, which occurring around the freezing temperature Tf = 40 K. Further analysis of the isothermal remanent magnetization (MIRM) suggests the existence of an intensive magnetic frustration state, which leads to stable residual magnetization without decaying under a long time span. More than that, based on the corresponding fitting parameters (τ0 = 8 × 10−12 s, zv = 6.32 and T0 = 56.2 K), the SG state in the sample is further confirmed. The following detailed analyses reveal that the competitions between antiferromagnetic (AFM) and ferromagnetic (FM) interactions definitely exist in MgGaFeO4, which should be the response to motivate the SG behavior. [ABSTRACT FROM AUTHOR]

We report the Griffiths phase (GP) and transport behavior in the quaternary antiperovskite nitrides Ge1−xSnxNFe3 by a series of systematical magnetic susceptibility and thermoelectric behavior measurements. All the corresponding fitting exponent parameters λGP = 0.852 and 0.854 completely satisfy 0 ≤ λ ≤ 1 in GP regions for Ge0.7Sn0.3NFe3 and Ge0.8Sn0.2NFe3, respectively, indicating the different ferromagnetic concentrations in the system. An observed structural transition from distorted tetragonal structure (I4/mcm) to cubic antiperovskite (Pm3m) with increasing dopants should be responsible for the GP in Ge1−xSnxNFe3, which results in a magnetic phase transition from ferromagnetism (FM) to antiferromagnetism (AFM). Furthermore, the studies of electrical transport properties indicate that the Ge1−xSnxNFe3 series of compounds perform a Fermi liquid behavior at low temperature while the stronger electron‐phonon scatterings are found in the high‐temperature region. In addition, the intensive electron–electron correlation is also determined since much higher value of lattice thermal conductivity κl than the one of electronic thermal conductivity κe. [ABSTRACT FROM AUTHOR]

We report the Griffiths phase (GP) and transport behavior in the quaternary antiperovskite nitrides Ge1−xSnxNFe3 by a series of systematical magnetic susceptibility and thermoelectric behavior measurements. All the corresponding fitting exponent parameters λGP = 0.852 and 0.854 completely satisfy 0 ≤ λ ≤ 1 in GP regions for Ge0.7Sn0.3NFe3 and Ge0.8Sn0.2NFe3, respectively, indicating the different ferromagnetic concentrations in the system. An observed structural transition from distorted tetragonal structure (I4/mcm) to cubic antiperovskite (Pm3m) with increasing dopants should be responsible for the GP in Ge1−xSnxNFe3, which results in a magnetic phase transition from ferromagnetism (FM) to antiferromagnetism (AFM). Furthermore, the studies of electrical transport properties indicate that the Ge1−xSnxNFe3 series of compounds perform a Fermi liquid behavior at low temperature while the stronger electron‐phonon scatterings are found in the high‐temperature region. In addition, the intensive electron–electron correlation is also determined since much higher value of lattice thermal conductivity κl than the one of electronic thermal conductivity κe. [ABSTRACT FROM AUTHOR]

This article, titled "Yellow bullous striae distensae," discusses a case of a 25-year-old male with severe dysphagia from dermatomyositis who presented with a yellow linear bullous eruption over his inner arms. The diagnosis of yellow bullous striae distensae was made, which is often associated with pregnancy, rapid weight gain, or drug-induced factors such as corticosteroids. The cutaneous finding led to investigations that revealed elevated total bilirubin, low albumin, increased body mass index, and gonadal dysfunction. Yellow bullous striae distensae are benign but can serve as helpful diagnostic clues for systemic symptoms. [Extracted from the article]

In this paper, we report a spin-glass (SG) behavior by comprehensive magnetic measurements in spinel compound ZnCoTiO4. The temperature dependence of DC magnetization exhibits a strong irreversibility under zero field cooled and field cooled processes. At the same time, AC susceptibility measurement reveals that the peak position moves towards high temperature with increasing frequency. These results unanimously indicate that a magnetic frustration behavior has occurred in this system. In addition, the relevant parameters (T0 = 14.4 K, τ0 = 8.3165 × 10−11 s, zν = 4.53) are observed by the data of AC susceptibility measurement, suggesting a typical SG behavior. The magnetic relaxation behavior (MIRM vs. t) further manifests a SG behavior in ZnCoTiO4. Furthermore, the origin of SG behavior in ZnCoTiO4 may be contributed to atomic disorders or the competition between ferromagnetic (FM) and antiferromagnetic (AFM) interactions, or both. [ABSTRACT FROM AUTHOR]

We report studies of the complex magnetic ordering, pressure-induced magnetic properties, large exchange bias (EB), spin-glass (SG), critical behavior, and electron spin resonance (ESR) in spinel Co2TiO4. The magnetic compensation behavior occurs in the vicinity of the compensation temperature Tcomp ∼ 32.5 K (defined as the susceptibility χZFC = χFC = 0), which can be attributed to the behavior that the magnetization of two bulk sublattices balances each other completely. The nature of this unusual case is demonstrated by the spin direction upon applied field and A–B sublattice (site) coupling. Specifically, the values of exchange integrals JAA and JBB play a crucial role at lower and higher temperatures, respectively. It is prominent that intrinsic coercivity Hcj increases by 168% at a pressure of 1000 MPa, from which we illustrate the antiferromagnetic (AFM) transition based on magnetic hysteresis loops M(H) and temperature dependent magnetization M(T) curves. The SG behavior of Co2TiO4 is confirmed by a series of reliable measurements and fitting parameters (τ0, zv), and a large EB field is also found through the asymmetry in the M(H) curve. Besides, the critical behavior of Co2TiO4 is studied initially in our present work, and the critical exponents (β, γ, and δ) indicate long-range ferromagnetic (FM) coupling accompanied by a short-range interaction in Co2TiO4. [ABSTRACT FROM AUTHOR]

The crystal structure, electromagnetic properties and magnetocaloric effect (MCE) of ternary iron-based ZnFe3N nitride have been investigated systematically. The density of states (DOS) calculation combined with theoretical model analysis suggests that ZnFe3N has a second-order ferromagnetic phase transition process existing in the cubic system. Its saturation magnetization (Ms) is about 108.3 emu/g at 5 K. The maximum values of magnetic entropy change (|ΔSM| = 2.2984 J/kg K) and relative cooling power (RCP = 247.0671 J/kg) are calculated from the measurements at a magnetic field change ΔH = 50 kOe, respectively. [ABSTRACT FROM AUTHOR]

The article describes the case of a 50-year-old woman who presented with an eruption over her left face for two months duration and with long-standing recurrent erythema and oedema over the same area, worsening with sun exposure, and was diagnosed with cutaneous lupus erythematosus.