We describes a controllable synthesis procedure for growing a-Ee2O3 and Ee3O4 nanowires. High magnetic hematite a-Fe2O3 nanowires are successfully grown on Fe0.5Ni0.5 alloy substrates via an oxide assisted vapor-solid...We describes a controllable synthesis procedure for growing a-Ee2O3 and Ee3O4 nanowires. High magnetic hematite a-Fe2O3 nanowires are successfully grown on Fe0.5Ni0.5 alloy substrates via an oxide assisted vapor-solid process. Experimental results also indicate that previous immersion of the substrates in a solution of oxalic acid causes the grown nanowires to convert gradually into magnetite （Fe3O4） nanowires. Additionally, the saturated state of Fe3O4 nanowires is achieved as the oxalic acid concentration reaches 0.75 mol/L. The average diameter and length of nanowires expands with an increasing operation temperature and the growth density of nanowires accumulates with an increasing gas flux in the vapor-solid process. The growth mechanism of a-Fe2O3 and Fe3O4 nanowires is also discussed. The results demonstrate that the entire synthesis of nanowires can be completed within 2 h.展开更多
The structure of a-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which i...The structure of a-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.展开更多
The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz-Gilbert equation. The evolutions of the magnetic d...The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz-Gilbert equation. The evolutions of the magnetic domain morphology are studied, and our analyses show that the magnetization reversal process is affected by the interaction between the moving domain wall and the existing nonmagnetic particles. This interaction strongly depends on the size of the particles, and it is found that particles with a particular size contribute the most to magnetic hardening.展开更多
文摘We describes a controllable synthesis procedure for growing a-Ee2O3 and Ee3O4 nanowires. High magnetic hematite a-Fe2O3 nanowires are successfully grown on Fe0.5Ni0.5 alloy substrates via an oxide assisted vapor-solid process. Experimental results also indicate that previous immersion of the substrates in a solution of oxalic acid causes the grown nanowires to convert gradually into magnetite （Fe3O4） nanowires. Additionally, the saturated state of Fe3O4 nanowires is achieved as the oxalic acid concentration reaches 0.75 mol/L. The average diameter and length of nanowires expands with an increasing operation temperature and the growth density of nanowires accumulates with an increasing gas flux in the vapor-solid process. The growth mechanism of a-Fe2O3 and Fe3O4 nanowires is also discussed. The results demonstrate that the entire synthesis of nanowires can be completed within 2 h.
基金The authors gratefully acknowledge the support of the National Natural Science Foundation of China (NO.50071057), and the support of the National Synchrotron Radiation Laboratory and Center Foundation (Hefei), China.
文摘The structure of a-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.
文摘The magnetization reversal process and hysteresis loops in a single crystal α-iron with nonmagnetic particles are simulated in this work based on the Landau-Lifshitz-Gilbert equation. The evolutions of the magnetic domain morphology are studied, and our analyses show that the magnetization reversal process is affected by the interaction between the moving domain wall and the existing nonmagnetic particles. This interaction strongly depends on the size of the particles, and it is found that particles with a particular size contribute the most to magnetic hardening.
