Oral Presentation Title: Free Layer Ferromagnetic Thickness Dependence of the Field-Like Spin-Orbit Torque with Spin Rotation

Spin-orbit torques have been at the forefront of spintronics research due to their applications in next-generation magnetic memories. Spin-orbit torques can be further broken down into two distinct areas of interest - damping-like torques and field-like torques. However, compared to the damping-like torque, the field-like torque is much less studied due to the complication of the Oersted field, which has the same symmetry.

We propose the use of spin rotation to generate field-like torque with a distinct symmetry from the Oersted field, allowing an accurate extrapolation of the field-like spin-orbit torque. The general device structure is PML/Cu/FM, where PML is a perpendicularly magnetized layer, and FM is an in-plane magnetized layer. We perform electrical transport measurements to quantify the field-like torque acting on the FM layer.

We observe the field-like torque to be inversely proportional to the thickness of the FM layer, suggesting that it arises from the spin current generated by the PML. Our result helps understand the origin of field-like spin-orbit torque.