Structure, magnetic and transport properties of polycrystalline Fe<sub>3</sub>O<sub>4</sub>–Ge nanocomposite films
Mi, W B; Shen, J J; Hou, D L; Li, X L; Jiang, E Y; Bai, H L; Mi, W B; Tianjin Key laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, People's Republic of China; Shen, J J; Tianjin Key laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, People's Republic of China; Department of Mathematics and Physics, Shijiazhuang Railway Institute, Shijiazhuang 050043, People's Republic of China; Hou, D L; Department of Physics, Hebei Normal University, Shijiazhuang 050016, People's Republic of China; Li, X L; Department of Physics, Hebei Normal University, Shijiazhuang 050016, People's Republic of China; Jiang, E Y; Tianjin Key laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, People's Republic of China; Bai, H L; Tianjin Key laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, People's Republic of China;
Журнал:
Journal of Physics D: Applied Physics
Дата:
2008-03-07
Аннотация:
Structure, magnetic and transport properties of polycrystalline Fe<sub>3</sub>O<sub>4</sub>–Ge nanocomposite films fabricated using a reactive cosputtering method have been examined. It is found that with the increase in Ge content, the Fe<sub>3</sub>O<sub>4</sub> grain size decreases and the crystallization of the grains becomes poor. The films are ferromagnetic at room temperature, and their saturation magnetization decreases with the increase in Ge content. The room-temperature resistivity, much higher than that of pure polycrystalline Fe<sub>3</sub>O<sub>4</sub> films, increases with increasing Ge content because of the poor crystallization and the appearance of Ge barriers at the grain boundaries. Meanwhile, the negative magnetoresistance also decreases from ∼4.4% to ∼1.9% as the Ge content increases from 0 to 38 at%, which can be explained by the fact that the crystallization of Fe<sub>3</sub>O<sub>4</sub> grains is disturbed by the increasing Ge content.
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