Al置換BaMフェライト薄膜の磁気特性  [in Japanese] Magnetic Characteristics of Al-substituted BaM Ferrite Films  [in Japanese]

Al-substituted Ba ferrite (Al-BaM) films with a composition of BaAl_xFe_<12-x>O_<19>(Al content x=0,1,2) were deposited on SiO_x/Si wafers with Pt seed layers. A postannealing process and high substrate temperature T_s are necessary to crystallize the films. With an increase of the Al content x in Al-BaM ferrite films, the saturation magnetization 4πM_s decreased, while perpendicular coercivity H_c⊥ increased, reaching over 3.3kOe. The perpendicular squareness ratio S_⊥ was increased to about 0.9 by substitution of Al for Fe. The Al-BaM ferrite films with suitable H_c⊥ and large S_⊥ prepared in this study may be applicable as perpendicular magnetic recording layers with low noise levels.