Papers by Author: Feng Ming Zhang

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Authors: S.K. Ren, G.B. Ji, Song Ling Huang, Q.Q. Cao, Feng Ming Zhang, You Wei Du
Abstract: We have investigated the magnetic properties and magnetostriction of ZnxNi1-xMnSb compounds prepared by solid state reaction method. It is found that for x less than 0.6 the magnetization of ZnxNi1-xMnSb almost remains unchanged. However, when x is larger than 0.6 the magnetization starts to drop linearly. Experimental result indicates that at low Zn concentrations, x < 0.7, the Curie temperature (TC) decreases with increasing Zn concentration x. However, when x > 0.7, the Curie temperature increases distinctly with increasing x. The Zn concentrartion dependence of magnetostrictive ceofficient is also studied. The experimental curve shows that when x < 0.6 the value of magnetostriction coefficient for ZnxNi1-xMnSb decreases linearly with the increasing Zn concentration x. However, when x is above 0.6, the magnetostrictive ceofficient raises distinctly. By analyzing the XRD pattern, the structures of the materials are examined and the relationship between the properties and the structures are discussed. A structural phase transition is observed. It has been indicated that the structure plays an important role in the magnetic and magnetostrictive properties of the system.
Authors: Shui Yuan Chen, Zhi Gao Huang, Heng Lai, Rongquan Gai, Feng Ming Zhang, You Wei Du
Abstract: Ferromagnetic (FM) La2/3(Ca0.6Ba0.4)1/3MnO3 and antiferromagnetic (AFM) NiO nanoparticles were synthesized using sol-gel method, respectively. La2/3(Ca0.6Ba0.4)1/3MnO3 (1 mol)/ x NiO (x= 0, 0.05 and 0.15mol) composites with the coated NiO were prepared. The experimental results indicate that, both phases of LCBMO and NiO coexist clearly in the composites and the sizes of the NiO nanoparticles in the intergranular region between the LCBMO particles are very small; the interface of NiO influences evidently the value of MR and it is found that the tunneling MR for x=0.05 is the largest in three samples. The magnetoresistance behavior has been explained by two-level model of tunneling magnetoresistance and percolation model well.
Authors: Zhi Gao Huang, Qian Feng, Yong Shen Li, Feng Ming Zhang, You Wei Du
Abstract: In this paper, the spin configuration and the configurational anisotropy of the clusters were studied by Monte Carlo simulations. An easy magnetization directions and a configurational anisotropy were found for the clusters using the hysteresis and spin configurations in different magnetization processes, and the simulated natural angle and energy distribution. It is considered that the configurational anisotropy is mainly attributed to the non-uniformity in spin configurations.
Authors: Zhi Gao Huang, Yingbin Lin, Yan Min Yang, Feng Ming Zhang, You Wei Du
Abstract: In this paper, based on 4×4 matrix method, we present theoretical calculations of the polar magneto-optical Kerr effect for Co/Pt and MnBi multilayered films, and NixSiO2(1-x) granular films. The calculated results indicate that, (1) the simulated Kerr spectra as a function of photo-energy are in good agreement with experimental ones; (2) the maxima and the periodical and damped oscillation appear in the Kerr spectra curve with the magnetic thickness, which is important for design of the material in the future; (3) the structure of interfacial layer affect greatly the Kerr spectra, which is significant for the processing of magneto-optical material.
Authors: Qian Feng, Qing Ying Ye, Zhen Zhen Wen, Li Qin Jiang, Zhi Gao Huang, Feng Ming Zhang, You Wei Du
Abstract: A ferromagnetic monolayer with competing long-range dipolar interaction, short-range interaction and magnetic uniaxial anisotropy is studied using Monte Carlo simulation. Striped domain patterns are found and reveal the microstructure of the magnetization transition at the ground state via the competing between dipolar interaction and uniaxial anisotropy. We present the finite temperature phase diagram and find a temperature-induced magnetization reorientation from out-of-plane to in-plane phase. The influence of the various interactions on the structure of the striped phase and reorientation behavior has been discussed.
Authors: Zhi Gao Huang, Heng Lai, Jian Min Zhang, Jia Xin Li, Feng Ming Zhang, You Wei Du
Abstract: In this paper, we simulate the magnetization dynamic processes of the multilayer films, and calculate their hysteresis loop areas using Monte Carlo method. The simulated results indicate that, the size and anisotropy strength of the anisotropy multilayer films influence evidently the dynamic phase transition, and the phase transition temperature increases with enhancing values of the anisotropy constant and layer thickness. It is also found that, with increasing number of layers of films, the value of α decreases, while the magnitudes of β and γ increase. On the contrary, with increasing anisotropy strength, the value of α increases, while the magnitudes of β and γ reduce.
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