Damping of spin dynamics in nanostructures: An ab initio study

D. Steiauf and M. Fähnle
Phys. Rev. B 72, 064450 – Published 30 August 2005

Abstract

Based on the Fermi surface breathing model of Kamberský, a phenomenological extension of the ab initio density-functional electron theory is used to derive an equation of motion for the spin dynamics in magnets. It is shown that even in the simple case of a homogeneous magnetization M the damping term (1M)M×[αdMdt] of the commonly used Gilbert equation with the damping scalar α has to be replaced by a term of the form (1M)M×[α͇(M)dMdt] with a damping matrix α͇ which depends on the orientation of M. Explicit calculations are performed for bulk, monolayers, and monatomic wires of Fe, Co, and Ni. The variation of α͇ with an orientation of M is quite substantial already for the bulk materials (up to a factor of 4 in hcp Co) but most dramatic in the monolayers and monatomic wires in which for some orientations the damping is even zero. This represents an additional option for optimizing the magnetization reversal process in a magnetic nanostructure. It is shown that there is no simple relation between damping and magnetic anisotropy energy.

    • Received 28 April 2005

    DOI:https://doi.org/10.1103/PhysRevB.72.064450

    ©2005 American Physical Society

    Authors & Affiliations

    D. Steiauf and M. Fähnle*

    • Max-Planck-Institut für Metallforschung, Heisenbergstraße 3, 70569 Stuttgart, Germany

    • *Electronic address: faehnle@mf.mpg.de

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    Issue

    Vol. 72, Iss. 6 — 1 August 2005

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