中国物理B ›› 2008, Vol. 17 ›› Issue (9): 3499-3504.doi: 10.1088/1674-1056/17/9/060
陈苗根1, 姜伟棣1, 叶高翔2, 焦志伟3, 冯春木4
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)†
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.
中图分类号: (Magnetic properties of monolayers and thin films)