制备条件和退火处理对Fex/(In2O3)1-x颗粒膜结构、磁性及巨磁电阻的影响

用射频溅射法成功制备了金属／半导体型颗粒膜Fex／(In2O3)1-x实验结果表明样品的微结构、磁性和巨磁电阻效应受制备条件(如本底真空度、衬底温度、溅射电压等)以及热退火处理的强烈影响。较高的衬底温度有利于基体In2O3的晶化和Fe颗粒的成长。适当的热退火能促使Fe颗粒生长，使晶格畸变减小，从而改善膜的微结构。室温下，磁性测量表明样品具有超顺磁性，符合朗之万方程。高温退火后，颗粒的大小已超过单畴粒子的临界尺寸，引起矫顽力下降。

The effects of preparation conditions and thermal annealing on the microstructure, magnetic properties and magnetoresistance of Fex/(In2O3)1-x granular films

Metal/semiconductor Fe__x_(In_2O_3)_(1-_x_) granular films were prepared successfully by the rf-sputtering method. The experimental results show that the microstructure, magnetic properties and magnetoresistance effects were affected strongly by preparation conditions (such as background vacuum degree, substrate temperature or sputtering voltages) and thermal annealing. The higher substrate temperature was in favor of the crystallization of In_2O_3 matrix and the growth of the Fe particles size. Appropriate annealing can improve the microstructure of the films due to the growth of Fe particles and the decrease of the distortion of the crystal lattice. At room temperature, the films show superparamagnetic behaviors and were fitted well by the Langevin equation. After high temperature annealing, the Fe particles size has exceeded the critical size of the single domain leading to the decrease of the coercivity of the sample.