Saturation of magnetic films with spin-polarized current in presence of magnetic field

TL;DR

This paper investigates how perpendicular magnetic fields influence the saturation of ferromagnetic films with spin-polarized currents, revealing the existence of a critical current for stable saturation and analyzing vortex-antivortex structures.

Contribution

It provides a theoretical analysis of magnetic field effects on spin-current-induced saturation, introducing the concept of a critical current for stable saturation and validating results with simulations.

Findings

Magnetic field direction affects saturation current $J_s$.

Existence of a critical current $J_c$ for stable saturation.

Magnetic field influences vortex-antivortex structures.

Abstract

Influence of perpendicular magnetic field on the process of transversal saturation of ferromagnetic films with spin-polarized current is studied theoretically. It is shown that the saturation current $J_s$ is decreased (increased) in case of codirected (oppositely directed) magnetic field and current. There exists a critical current $J_c>J_s$ which provides "rigid" saturation -- the saturated state is stable with respect to the transverse magnetic field of any amplitude and direction. Influence of the magnetic field on the vortex-antivortex crystals, which appear in pre-saturated regime, is studied numerically. All analytical results are verified using micromagnetic simulations.