GdFeCo/AlN/TbFeCo薄膜的变温磁化性能研究

Temperature Dependence of Magnetization of Readout Layers in GdFeCo/AlN/TbFeCo Multilayer Films

用磁控溅射法制备了GdFeCo/AlN/TbFeCo静磁耦合多层薄膜。振动样品磁强计和克尔磁滞回线测试装置的测试结果表明 :2 5℃不加外磁场时GdFeCo/AlN/TbFeCo静磁耦合多层薄膜读出层 (GdFeCo)的极向克尔角为零 ,读出层呈平面磁化 ;12 5℃不加外场时读出层的克尔角最大 (0 .5 4°) ,读出层的磁化方向为垂直磁化 ;随着温度增高 ,读出层由平面磁化转变为垂直磁化 ,在 75℃到 12 5℃温度范围内读出层磁化方向很快从平面磁化转变为垂直磁化。对磁化过程的机理研究表明 :饱和磁化强度和有效各向异性常量影响读出层磁化方向的转变过程 ,但主要受读出层饱和磁化强度的影响 ;在较高温度时读出层的磁化强度较小 ,退磁场能较小 ,在静磁耦合作用下 ,使GdFeCo读出层的磁化方向发生转变。制备的GdFeCo/AlN/TbFeCo静磁耦合多层薄膜适合作CAD

The magnetostatically coupled multilayer films (GdFeCo/AlN/TbFeCo) were prepared by sputtering method. The measuring results by vibrating sample magnetometer and Kerr rotation hysteresis loop measurement indicate that the Kerr rotation angle of the readout layer (GdFeCo) at no external field is almost zero, and the magnetization direction of the readout layer is in-plane at 25 ℃; the Kerr rotation angle of the readout layer has a maximal value (0.54) at 125 ℃, the magnetization direction of the readout layer is perpendicular at 125 ℃; the magnetization orientation of the readout changes from in-plane to perpendicular with the raise of the temperature. The magnetization direction of the readout layer changes rapidly from 75 ℃ to 125 ℃. The magnetization mechanism of the films was studied. It was found that the magnetization reorientation of the GdFeCo layer is effected by the saturation magnetization and the effective anisotropy energy, but the transition occurs mainly as a result of the changes in the saturation magnetization. The saturation magnetization and the demagnetizing energy of the GdFeCo layer decrease with increasing temperature, and the transition of the GdFeCo layer from in-plane to perpendicular magnetization occurs. The films are suitable to be used as center aperture detection-magnetically superresolution (CAD-MSR) recording media.