中国物理B ›› 2002, Vol. 11 ›› Issue (2): 178-182.doi: 10.1088/1009-1963/11/2/314

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Magnetoresistance and magnetic properties of Fe3O4 nanoparticle compacts

李凤英1, 靳常青1, 孟凡斌2, 李养贤2, 王海3, 赵宏武3, 王常生3, 王荫君3, 詹文山3   

  1. (1)Institute of Physics and Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; (2)Material Test Center, Hebei University of Technology, Tianjing 300130, China; (3)State Key Laboratory of Magnetism, Institute of Physics and Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2001-07-03 修回日期:2001-09-29 出版日期:2002-02-13 发布日期:2005-06-13
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 59928101 and 59871063).

Magnetoresistance and magnetic properties of Fe3O4 nanoparticle compacts

Wang Hai (王海)a, Zhao Hong-Wu (赵宏武)a, Wang Chang-Sheng (王常生)a, Wang Yin-Jun (王荫君)a, Zhan Wen-Shan (詹文山)a, Li Feng-Ying (李凤英)b, Jin Chang-Qing (靳常青)b, Meng Fan-Bin (孟凡斌)c, Li Yang-Xian (李养贤)c    

  1. a State Key Laboratory of Magnetism, Institute of Physics and Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; b Institute of Physics and Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China; c Material Test Center, Hebei University of Technology, Tianjin 300130, China
  • Received:2001-07-03 Revised:2001-09-29 Online:2002-02-13 Published:2005-06-13
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 59928101 and 59871063).

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摘要： In this paper, we report on the magnetic properties of Fe3O4 nanoparticles with different grain sizes under different pressures. In all the samples, the saturated magnetization Ms shows a linear decrease with increasing pressure. The thickness of the magnetic dead layer on the nanoparticle surface under different pressures was roughly estimated, which also increases with increasing pressure. The transport measurements of the nanoparticle Fe3O4 compacts show that the low-field magnetoresistance (MR) value is insensitive to the grain size in a wide temperature range; however, the high-field MR value is dependent on grain size, especially at low temperatures. These experimental results can be attributed to the different surface states of the nanoparticles.

Abstract: In this paper, we report on the magnetic properties of Fe3O4 nanoparticles with different grain sizes under different pressures. In all the samples, the saturated magnetization Ms shows a linear decrease with increasing pressure. The thickness of the magnetic dead layer on the nanoparticle surface under different pressures was roughly estimated, which also increases with increasing pressure. The transport measurements of the nanoparticle Fe3O4 compacts show that the low-field magnetoresistance (MR) value is insensitive to the grain size in a wide temperature range; however, the high-field MR value is dependent on grain size, especially at low temperatures. These experimental results can be attributed to the different surface states of the nanoparticles.

Key words: nanoparticle, saturated magnetization, magnetoresistance

中图分类号:  (Other materials)

  • 75.47.Pq
75.50.Tt (Fine-particle systems; nanocrystalline materials) 75.60.Ej (Magnetization curves, hysteresis, Barkhausen and related effects) 75.70.Cn (Magnetic properties of interfaces (multilayers, superlattices, heterostructures))