Micromagnetic study of high-power spin–torque oscillator with perpendicular magnetization in half-metallic Heusler alloy spin valve nanopillar under external magnetic fields

• We investigated spin–torque oscillator in Co2MnSi spin-valve under magnetic fields.
• The narrow optimum current is broadened by introducing the surface anisotropy.
• The frequency dependences of out-of-plane and in-plane magnetic fields show linear and parabola.
• The results may give the guidance for designing Heusler-based spin–torque oscillator.

We investigated the high-power spin–torque oscillator in a half-metallic Heusler alloy Co2MnSi spin-valve nanopillars with perpendicular magnetization under external magnetic field using micromagnetic simulations. Our simulations show that the narrow optimum current of magnetization precession in the Heusler-based spin valve is broadened by introducing the surface anisotropy. The linear decrease of frequency with the out-of-plane magnetic field is obtained in our simulation. Additionally, the in-plane magnetic field dependence of frequency shows a parabolic curve which is explained by the magnetization trajectory tilting. Furthermore, we also discussed the decrease of output power using the excitation of non-uniform magnetization precession in the in-plane magnetic fields.