Current-induced transverse spin-wave instability in a thin nanomagnet

Phys Rev Lett. 2004 Jan 16;92(2):026602. doi: 10.1103/PhysRevLett.92.026602. Epub 2004 Jan 16.


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.