中国物理B ›› 2008, Vol. 17 ›› Issue (9): 3499-3504.doi: 10.1088/1674-1056/17/9/060

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Anomalous magnetic properties of an iron film system deposited on fracture surfaces of α-Al2O3 ceramics

陈苗根1, 姜伟棣1, 叶高翔2, 焦志伟3, 冯春木4   

  1. (1)Department of Physics, China Jiliang University, Hangzhou 310018, China; (2)Department of Physics, Zhejiang University, Hangzhou 310027, China; (3)Department of Physics, Zhejiang University, Hangzhou 310027, China;Department of Physics, China Jiliang University, Hangzhou 310018, China; (4)Test and Analysis Center, Zhejiang University, Hangzhou 310028, China
  • 收稿日期:2007-11-07 修回日期:2008-05-18 出版日期:2008-09-08 发布日期:2008-09-08
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10574109 and 50701037) and the Zhejiang Provincial Science and Technology Department of China (Grant No 2005C24008).

Anomalous magnetic properties of an iron film system deposited on fracture surfaces of $\alpha$-Al2O3 ceramics

Jiao Zhi-Wei(焦志伟)a)b), Chen Miao-Gen(陈苗根)b), Jiang Wei-Di(姜伟棣)b), Feng Chun-Mu(冯春木)c), and Ye Gao-Xiang(叶高翔)a)†   

  1. a Department of Physics, Zhejiang University, Hangzhou 310027, China; b Department of Physics, China Jiliang University, Hangzhou 310018, China; c Test and Analysis Center, Zhejiang University, Hangzhou 310028, China
  • Received:2007-11-07 Revised:2008-05-18 Online:2008-09-08 Published:2008-09-08
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10574109 and 50701037) and the Zhejiang Provincial Science and Technology Department of China (Grant No 2005C24008).

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摘要： An iron film percolation system is fabricated by vapour-phase deposition on fracture surfaces of α-Al2O3 ceramics. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurement reveals that the magnetic phase of the film samples evolve from a high-temperature ferromagnetic state to a low-temperature spin-glass-like state, which is also demonstrated by the temperature-dependent ac susceptibility of the iron films. The temperature dependence of the exchange bias field $H_{\rm e}$ of the iron film exhibits a minimum peak around the temperature $T$=5\,K, which is independent of the magnitude of the cooling field $H_{\rm cf}$. However, for $T > 10$\,K, (1) $H_{\rm e}$ is always negative when $H_{\rm cf}$=2\,kOe and (2) for $H_{\rm cf }$= 20\,kOe (1Oe$\approx$80\,A/m), $H_{\rm e}$ changes from negative to positive values as T increases. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase.

关键词: iron film, ceramics, exchange interactions, magnetic measurements

Abstract: An iron film percolation system is fabricated by vapour-phase deposition on fracture surfaces of $\alpha$-Al2O3 ceramics. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization measurement reveals that the magnetic phase of the film samples evolve from a high-temperature ferromagnetic state to a low-temperature spin-glass-like state, which is also demonstrated by the temperature-dependent ac susceptibility of the iron films. The temperature dependence of the exchange bias field $H_{\rm e}$ of the iron film exhibits a minimum peak around the temperature $T$=5 K, which is independent of the magnitude of the cooling field $H_{\rm cf}$. However, for $T > 10$ K, (1) $H_{\rm e}$ is always negative when $H_{\rm cf}$=2 kOe and (2) for $H_{\rm cf }$= 20 kOe (1Oe$\approx$80 A/m), $H_{\rm e}$ changes from negative to positive values as T increases. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase.

Key words: iron film, ceramics, exchange interactions, magnetic measurements

中图分类号:  (Magnetic properties of monolayers and thin films)

  • 75.70.Ak
75.30.Cr (Saturation moments and magnetic susceptibilities) 75.30.Sg (Magnetocaloric effect, magnetic cooling) 75.50.Bb (Fe and its alloys) 75.60.Ej (Magnetization curves, hysteresis, Barkhausen and related effects) 81.15.Kk (Vapor phase epitaxy; growth from vapor phase)