共查询到20条相似文献,搜索用时 31 毫秒
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《Physics letters. A》2019,383(18):2229-2234
In this work, the exchange bias behavior and magnetocaloric effect have been studied in Mn7Sn4 alloy. The X-ray powder diffraction pattern recorded at room temperature indicates that the sample crystallizes in a single phase with Ni2In-type hexagonal structure (space group ). The maximum magnetic entropy change value across paramagnetic/ferrimagnetic transition is about 3.3 J kg−1 K−1 under the magnetic field change of . With further cooling, the reentrant spin-glass-like state is obtained below 150 K, for which the exchange bias effect has been observed. The exchange bias field is ∼7.8 mT and ∼6.7 mT at when the cooling field is and 0.5 T, respectively. The magnetic behavior and the origin of exchange bias in Mn7Sn4 are discussed. 相似文献
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《Physics letters. A》2020,384(14):126281
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《Physics letters. A》2020,384(31):126811
Y2WO6 ceramics were fabricated via a solid-state reaction method and investigated structure stability, densification, microstructure, and dielectric properties at microwave frequency range. Y2WO6 crystallized in a monoclinic structure and stabilized to 1500 ∘C, beyond which the decomposition of Y6WO12 occurred. Y2WO6 ceramic could be sintered into a compact bulk at 1450 ∘C, which was characterized by a high relative density ∼ 97.6% and a dense microstructure. The favorable dielectric performances were achieved at 1450 ∘C with a relative permittivity , a quality factor GHz ( GHz), and a temperature coefficient of resonant frequency ppm/∘C. The MW properties of Y2WO6 suggest that it could be useful candidate material for low-loss dielectric resonators. 相似文献
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We have investigated the spin and orbital moments of Ir-based double perovskites with (n = 3, 4, 5) states by local spin-density approximation with spin-orbital coupling and Hubbard correlation (LSDA+SOC+U). Our calculations reveal that the ratio of orbital to spin momentum approaches to certain values for the double perovskites with different 5dn (n = 3, 4, 5) shell fillings. Based on d orbits, a spin-orbital coupling model with exchange splitting is proposed and it can well describe the ratio of angular momentums for the compounds. Our model calculations reveal that is determined by the exchange splitting, spin-orbital coupling as well as the state of shell filling. Our model is well corroborated by the experiments and density-functional calculations. 相似文献
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With the help of the nonequilibrium Green's function technique, we theoretically analyze the thermospin property through a typical T-shaped spin valve with spin-flip scattering in the linear regime. The influences of spin-flip coefficient of interdot λ, spin-flip coefficient of intradot η and interdot hopping coefficient on thermospin property are discussed. As interdot hopping coefficient t is equal to energy level ε, the spectrum of shows Fano-like effect with ε variation. Antiresonance position of is almost unchanged and its width becomes narrower with ε increasing. Spin thermopower is close to the maximum of the peak and charge thermopower is equal to zero for . As a result, the pure spin thermopower can be obtained, which means that a pure spin current may be produced by a temperature gradient in our system. It is found that spin figure of merit can reach a considerable value by adjusting key parameters of the system, such as Δt, β, α, ?. The typical T-shaped spin valve can be treated as a stable thermospin battery which allows to convert the heat energy to spin voltage, thus produces the pure spin current in the device. 相似文献
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The behavior of composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al2O3 to stable tetrahedral aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction. 相似文献