Current-induced noise and damping in non-uniform ferromagnets

Abstract

In the presence of spatial variation of the magnetization direction, electric current noise causes a fluctuating spin-transfer torque that increases the fluctuations of the ferromagnetic order parameter. By the fluctuation-dissipation theorem, the equilibrium fluctuations are related to the magnetization damping, which in non-uniform ferromagnets acquires a nonlocal tensor structure. In biased ferromagnets, shot noise can become the dominant contribution to the magnetization noise at low temperatures. Considering spin spirals as a simple example, we show that the current-induced noise and damping is significant.

5 pages, 1 figure

References in corpus (2)

• Identification of the dominant precession damping mechanism in Fe, Co, and Ni by first-principles calculations
• Inhomogeneous Gilbert damping from impurities and electron-electron interactions

Cited by in corpus (3)

• Transverse spin diffusion in ferromagnets
• Theory of spin magnetohydrodynamics
• Quasi-reversible Magnetoresistance in Exchange Spring Tunnel Junctions