MnBiAl薄膜的磁光及磁性能研究

用真空电子束蒸发制备了MnBi_xAl_0.15薄膜.当0.4≤x≤0.7时，MnBi_xAl_0.15薄膜的Kerr角与MnBi_x薄膜相比有显著增大；而当x＞0.7时，MnBi_xAl_0.15的Kerr角则比MnBi_x的要不，633nm波长测量时，MnBi_{0.5Al0.15的Kerr角为2.75°，而相对应的MnBi0.5薄膜只有1.56°.MnBi05Al0.15薄膜的室温饱和磁化强度Ms为3×10⁵A/m，比MnBi0.5薄膜的Ms(4×10⁵A/m)要小.推测当0.4≤x≤0.7时，Al可能部分占据Bi空位和部分取代Mn位，由于晶格收缩使得Mn 3d电子与Bi 6p电子的杂化概率增大，从而导致其Kerr效应增强.关键词：}

Magneto-Optical and Magnetic Properties of MnBiAl Thin Films

The Kerr rotation of MnBi_xAl_0.15(0.4≤x≤0.9) thin films with and Al protective layer as a function of the Bi concentration, x, has been investigated. Compared with MnBi_x thin films, it is found that a large enhancement of Kerr rotation appears in the MnBi_xAl_0.15 thin films with 0.4≤x≤0.7, but no enhancement of Kerr rotation appears when x is greater than 0.7. When x=0.5, a maximum Kerr rotation of 2.75° is observed at 633nm for the MnBi_0.5Al_{0.15 thin film, which is much larger than that of 1.56° for the MnBi0.5 thin film. For the MnBixAl0.15 thin films with 0.4≤x≤0.7, the c lattice shrinking may result in a stronger hybridization between Bi 6p and Mn 3d states, which also should be responsible for the large enhancement of Kerr rotatio. In addition, the saturation magnetization Ms is reduced from 4×10⁵A/m for the MnBi0.5 thin film to 3×10⁵A/m for the MnBi0.5Al0.15 thin film, suggesting that some of Al may also substitute for Mn at the octahedrtal sites.}