Spin–orbit torque magnetization switching is an efficient method to control magnetization. In perpendicularly magnetized films, two types of spin–orbit torque are induced by driving a current: a damping-like torque and a field-like torque. The damping-like torque assists magnetization switching, but a large field-like torque pushes the magnetization towards the in-plane direction, resulting in a larger critical switching current density and making deterministic switching challenging. Control of the field-like torque strength is difficult because it is intrinsic to the material system used. Here, we show that the field-like term can be suppressed in a spin–orbit ferromagnetic single layer of (Ga,Mn)As by a current-induced Oersted field due to its non-uniform current distribution, making the damping-like torque term (the result of strong Dresselhaus spin–orbit coupling) dominant. The Oersted field can be controlled by the film thickness, resulting in an extremely low switching current density of 4.6 × 10⁴ A cm^–2. This strategy can thus provide an efficient approach to spin–orbit torque magnetization switching.

自旋轨道转矩磁化切换是控制磁化的有效方法。在垂直磁化的薄膜中，通过驱动电流会产生两种类型的自旋轨道转矩：类似阻尼的转矩和类似场的转矩。类似于阻尼的转矩有助于磁化切换，但是较大的类似于磁场的转矩会将磁化推向平面内方向，从而导致较大的临界开关电流密度，并给确定性切换带来挑战。难以控制像场一样的扭矩强度，因为它是所用材料系统固有的。在这里，我们证明了（Ga，Mn）As的自旋轨道铁磁单层中，由于其电流分布不均匀，可以通过电流感应的Oersted磁场来抑制类似磁场的项，使类似阻尼的转矩项（强Dresselhaus自旋-轨道耦合的结果）占主导地位。Oersted场可以通过薄膜厚度来控制，从而导致4.6×10的极低开关电流密度⁴  A厘米^–2。因此，该策略可以为自旋轨道转矩磁化切换提供有效的方法。