Distortion of the Stoner-Wohlfarth astroid by a spin-polarized current

Abstract

The Stoner-Wohlfarth astroid is a fundamental object in magnetism. It separates regions of the magnetic field space with two stable magnetization equilibria from those with only one stable equilibrium and it characterizes the magnetization reversal of nano-magnets induced by applied magnetic fields. On the other hand, it was recently demonstrated that transfer of spin angular momentum from a spin-polarized current provides an alternative way of switching the magnetization. Here, we examine the astroid of a nano-magnet with uniaxial magnetic anisotropy under the combined influence of applied fields and spin-transfer torques. We find that spin-transfer is most efficient at modifying the astroid when the external field is applied along the easy-axis of magnetization. On departing from this situation, a threshold current appears below which spin-transfer becomes ineffective yielding a current-induced dip in the astroid along the easy-axis direction. An extension of the Stoner-Wohlfarth model is outlined which accounts for this phenomenon.

arXiv comment8 pages, 6 figures

References in corpus (5)

• Current-driven Magnetization Reversal and Spin Wave Excitations in Co/Cu/Co Pillars
• Magnetic Anisotropy of a Single Cobalt Nanoparticle
• Current Induced Magnetization Switching in Small Domains of Different Anisotropies
• Angular Dependence of Spin-Torque Critical Currents in CPP-GMR Read Heads
• Angular-dependence of magnetization switching for a multi-domain dot: experiment and simulation

Cited by in corpus (3)

• Spin-transfer assisted thermally activated switching distributions in perpendicularly magnetized spin valve nanopillars
• Temperature dependence of the switching field distributions in all-perpendicular spin-valve nanopillars
• Materials Relevant to Realizing a Field-Effect Transistor based on Spin-Orbit Torques