Quasistatic rotation of the magnetization of thin films

The direction of the mean magnetization during magnetization rotation in uniaxial thin films with a reverse field which increased quasistatically has been investigated. The analysis of the observations shows that several effects happen during the magnetization rotation: reversible influence of nonlinear torques in the free ripple region, blocking, irreversible torques, deblocking, stabilization by the intrinsic demagnetizing field, locking, and partial rotation. At the critical astroid of the single-domain theory, the films do not show any critical effect during the magnetization rotation. The critical effects are given by blocking and locking. These film properties are determined by the structure constant S. Even in the nonblocked-ripple region, the mean magnetization deviates from the direction expected, according to the single-domain theory or the linear-ripple theory. This indicates the existence of nonlinear torques. After passing the blocking curve, the intrinsic demagnetizing field contributes dominantly to the nonlinear torque. This field is responsible for the stabilization of the magnetization.