Current-induced transverse spin wave instability in a thin nanomagnet

TL;DR

This paper demonstrates that an unpolarized current can induce a transverse spin-wave instability in a thin nanomagnet through spin-transfer torque, occurring only with asymmetric contacts and a specific current direction.

Contribution

It reveals a novel current-induced spin-wave instability mechanism in thin nanomagnets caused by unpolarized currents and contact asymmetry.

Findings

Instability occurs only with asymmetric contacts.

The instability is driven by spin-transfer torque.

It is dependent on current direction.

Abstract

We show that an unpolarized electric current incident perpendicular to the plane of a thin ferromagnet can excite a spin-wave instability transverse to the current direction if source and drain contacts are not symmetric. The instability, which is driven by the current-induced ``spin-transfer torque'', exists for one current direction only.