缓冲层对Fe_3O_4薄膜的结构与电磁性能影响

Influence of Buffer Layers on the Structural and Electromagnetic Properties of Fe_3O_4 Films

利用直流反应磁控溅射法制备了厚度约100 nm成分单一的Fe3O4薄膜。对薄膜样品进行XRD测试,研究了不同缓冲层对薄膜结构的影响。结果表明:Fe3O4薄膜沉积在缓冲层上时,薄膜的各衍射峰与Fe3O4的尖晶石结构的衍射峰相似,以(311)峰为主峰;对薄膜表面的AFM测试结果表明引入缓冲层使得薄膜晶粒分布均匀,表面平整度较好,且可以有效地降低薄膜表面粗糙度,在La2/3Ca1/3Mn O3上沉积时均方根粗糙度最小(RMS=1.47 nm);通过对Fe3O4薄膜磁电阻效应的测试,发现引入缓冲层的Fe3O4薄膜均呈现负磁电阻效应,电阻变化率对外加磁场的灵敏度减小;由于引入缓冲层后薄膜的晶体结构发生改变,增加了磁畴壁的移动阻力,薄膜的矫顽力和剩磁提高。

Magnetite（Fe3O4） thin films of 100 nm in thickness have been prepared by DC reactive magnetron sputtering. The crystal structure of the films deposited with different buffer layers is detected by the X-ray diffraction（XRD）. The measurements indicate that the diffraction peaks of Fe3O4 films with different buffer layers similar to the spinel structure of Fe3O4. AFM measurements indicate that the film particles distribute evenly, the surface roughness and a fine microstructure are observed, the roughness of the film is reduced, and it reaches the minimum of RMS=1.47 nm with La2/3Ca1/3Mn O3 buffer layer. The negative magnetoresistance of Fe3O4 films is also tested. The results show that ΔR/R has a weak decreases trend of sensitivity to magnetic field. Hysteresis loops of sample indicate that the coercive and remanence ratio increase with different buffer layers.