Inhomogeneous Gilbert damping from impurities and electron-electron interactions

URL:http://link.aps.org/doi/10.1103/PhysRevB.78.020404 DOI:10.1103/PhysRevB.78.020404We present a unified theory of magnetic damping in itinerant electron ferromagnets at order q2 including electron-electron interactions and disorder scattering. We show that the Gilbert damping coefficient can be expressed in terms of the spin conductivity, leading to a Matthiessen-type formula in which disorder and interaction contributions are additive. In a weak ferromagnet regime, electron-electron interactions lead to a strong enhancement of the Gilbert damping.This work was supported in part by the NSF under Grants No. DMR-0313681 and No. DMR-0705460 as well as Fordham Research Grant