Temperature dependence of coercivity behavior in iron films on silicone oil surfaces

摘要

A new iron film system, deposited on silicone oil surfaces by vapor phase deposition method, has been fabricated and its microstructure as well as magnetic properties has been studied. It is found that the temperature dependence of the coercive field He (T) of the films exhibits a peak around a critical temperature T-crit = 10-15 K: for the temperature T < T-crit, H-C(T) increases with the temperature; if T > T-crit, however, it decreases rapidly and then approaches a steady value as T further increases. Our study shows that, for T > T-crit, the observed coercivity behavior is mainly dominated by the effect of the non-uniform single-domain particle size distribution, and for T < T-crit, the anomalous coercivity behavior may be resulted from the surface anisotropy, the surface effect and the characteristic internal stress distribution in the films. The influence of the shape and size of the particles on the thermal dependence of the magnetization is also investigated. (c) 2006 Elsevier B.V. All rights reserved.