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报道了“铁磁金属-半导体基体”Fe_x(In_2O_3)_(1-x)颗粒膜的磁性研究。根据低场磁化率X(T)温度关系和不同温度下的磁滞回线研究表明:膜中的Fe颗粒有大小不同的两种尺度,随温度降低,颗粒膜的磁特性由超顺磁态转变为超顺磁和铁磁的混磁态,最后在10K变为类反铁磁态;在截止温度以上,其Ms(T)关系符合Bloch的T~(3/2)定律。研究了样品磁性(矫顽力和饱和磁化强度)随铁颗粒尺寸的变化规律;高温磁性测量表明:纳米Fe颗粒所构成的颗粒膜样品的Curie温度T_c明显低于块状铁的数值。探讨了饱和磁化强度和Curie温度随颗粒尺寸变化的原因。
The magnetism study of Fe_x (In_2O_3) _ (1-x) granular film of “ferromagnetic metal-semiconductor matrix” was reported. According to the temperature dependence of the low field magnetic susceptibility X (T) and the hysteresis loop at different temperatures, the results show that the Fe particles in the film have two sizes with different sizes. With the decrease of temperature, the magnetic properties of the granular film are changed from superparamagnetic state Into superparamagnetic and ferromagnetic mixed magnetic state, and finally become antiferromagnetic state at 10K; above the cut-off temperature, the Ms (T) relationship is in accordance with Bloch’s T ~ (3/2) law. The magnetic properties (coercivity and saturation magnetization) of the samples were investigated with the change of iron particle size. The high temperature magnetic measurements showed that the Curie temperature T_c of the granular film composed of nano-Fe particles was significantly lower than that of bulk iron. The reasons for the change of saturation magnetization and Curie temperature with particle size are discussed.