Spin–Orbit Torque and Current‐Driven Switching in Pt100‐yTby/Co/AlOx Trilayers

Abstract

Abstract To decrease the energy consumption for the electrical manipulation of magnetization, the enhancement of the spin Hall effect through alloying is widely investigated, but the use of rare earth elements is rarely mentioned. This work reports the modification of the spin Hall effect on Pt by doping rare earth Tb atoms. The spin–orbit torque (SOT) performance is significantly enhanced in Pt100‐yTby alloyed heavy metal (HM) layer. Compared with the Tb‐free sample, the damping‐like effective field per unit current density increases to 1.9 times in the samples with Tb content between 5% and 10%. The critical current density for magnetization reversal is greatly reduced by 65% in a device with Pt87Tb13 HM layer and the in‐plane assistant field as small as ±20 Oe is sufficient for the deterministic switching in the same device. By magneto‐optical Kerr effect imaging, it is confirmed that the increased in‐plane field can effectively compensate the Dzyaloshinskii–Moriya interaction (DMI), which not only helps to reduce the critical current, but also facilitates the domain wall motion and is beneficial for the switching process. All results show that the Pt‐Tb alloy is a competitive candidate for low‐power spintronic devices.

Keywords

• current‐induced magnetization switching
• domain wall motion
• Dzyaloshinskii–Moriya interaction
• Pt‐Tb alloy
• spin‐orbit torque