Current-Induced Domain Wall Motion in TbFeCo Wires With Perpendicular Magnetic Anisotropy

Current-induced domain wall motion in TbFeCo wires with perpendicular magnetic anisotropy has been directly observed by Kerr microscope. The moving direction of domain wall is opposite to the current direction, which is in agreement with the spin torque transfer theory. The critical current density found in TbFeCo is lower than 10⁷ A/cm², which is an order smaller than in other metallic materials reported so far. In addition, the critical current density gets increased with the increase of the pinning potential in TbFeCo thin film, which is also consistent with the theoretical prediction for a pinning dominant mechanism.