【摘要】 采用射频溅射法制备了纳米Fe-In2O3颗粒膜,研究了颗粒膜在低温下的两种特殊磁效应——巨磁电阻效应和磁性弛豫效应。磁电阻测量结果表明,当Fe体积分数为35%时,颗粒膜样品的室温磁电阻变化率(Δρ/ρ0)为4.5%,而在温度T=2K时,Δρ/ρ0达85%。根据颗粒膜低场磁化率-温度(χ-T)关系证实,在一定温度下,颗粒膜中纳米Fe颗粒表现出磁性弛豫效应,当截止温度TB=50K时,颗粒膜的磁特性由超顺磁性转变为铁磁性;在截止温度以上,其饱和磁化强度与温度关系符合Bloch的T3/2定律。更多还原

【Abstract】 Nanometer Fe-In₂O₃ granular films were fabricated by radio frequency sputtering. The particular magnetic effects, which are the giant magnetoresistance effect and the magnetic relaxation effect, of the granular films at low temperature have been studied.The measuring results of magnetoresistance show that the magnetoresistance ratio Δρ/ρ₀ value of the granular films sample with Fe volume percent of 35% is 4.5% at room temperature, and when T=2 K, Δρ/ρ₀ value reaches 85%. According to the dependence of low field susceptibility on temperature, it was found that the nanometer-sized Fe particles in granular films showed the magnetic relaxation effect at definite temperature. The magnetic property of granular films changes from super-paramagnetic into ferromagnetic at the blocking temperature T_B=50 K. Above the blocking temperature, the M_S（T） of the granular films follows the Bloch’s T^3/2 law.更多还原