Magnetic and Impedance Properties of Nanocomposite CoFe2O4/Co0.7Fe0.3 and Single‐Phase CoFe2O4 Prepared Via a One‐Step Hydrothermal Synthesis |
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| Authors: | Fenlian Zan Yongqing Ma Qian Ma Yuanfeng Xu Zhenxiang Dai Ganhong Zheng Mingzai Wu Guang Li |
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| Affiliation: | Anhui Key Laboratory of Information Materials and Devices, School of Physics and Materials Science, Anhui University, , Hefei, 230039 China |
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| Abstract: | Using a one‐step hydrothermal method and at different stirring speeds (Vs), we have synthesized different types of CoFe2O4‐based magnetic nanocrystalline samples. With increasing Vs, the sample changes from a nanocomposite of CoFe2O4/Co0.7Fe0.3 (CFO/CF) to single‐phase CoFe2O4 (CFO). The maximum magnetization, 88.9 emu/g, and coercivity, 3010 Oe, were obtained when Vs = 0. As Vs increases, the saturation magnetization Ms decreases, because the amount of soft magnetic CF phase decreases. A clear enhancement in the remanence, Mr, was observed, with the maximum Mr/Ms = 0.67; the coercivity Hc also exhibits a local maximum for the sample with Vs = 200 r/min. These trends can be explained well by the interplay between dipolar interaction, magnetocrystalline anisotropy, and shape anisotropy. The stirring speed also influences the impedance of the materials; the related mechanism is discussed. |
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