Ni_<80>Fe_<20>/Al-Oxide/Co接合におけるトンネル磁気抵抗比のNi_<80>Fe_<20>膜厚依存性  [in Japanese] Ni_<80>Fe_<20> Thickness Dependence of the TMR Ratio for Ni_<80>Fe_<20>/Al-Oxide/Co Junctions  [in Japanese]

Ferromagnetic tunneling junctions with various thicknesses of the first ferromagnetic layer were fabricated. Ni_<80>Fe_<20> and Co were used as the first ferromagnetic layer, and their thickness were varied between 10 and 200Å. The tunneling magnetoresistance (TMR) ratio decreased and the shape of the TMR curve changed with decreasing Ni_<80>Fe_<20> thickness, but changed only slightly with decreasing Co thickness. We calculated the TMR and magnetization curves by using a simple model that takes account of magnetic anisotropy to explain the change in the TMR ratio and the shape of the TMR curve with changing Ni_<80>Fe_<20> thickness.