Abstract
We present an ab initio theory of the Gilbert damping in ferromagnetic alloys with substitutional disorder. The theory is based on nonlocal torques that are represented by nonrandom, site-off-diagonal, and spin-independent matrices, which simplifies the configuration averaging. The formalism is developed for the relativistic tight-binding linear muffin-tin orbital (TB-LMTO) method and the coherent potential approximation (CPA). The CPA-vertex corrections play a crucial role for the internal consistency of the theory and for its exact equivalence to other first-principles approaches based on random local torques. The theory is illustrated by calculations for various random transition metal alloys: FeNi, FeCo, Heusler alloys, permalloy with impurities, Fe with vacancies, and stoichiometric FePt and CoPt alloys with a varying degree of L1 0 atomic long-range order. Results are in a reasonable agreement with other calculations and accessible experimental data.
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The authors thank Czech Science Foundation (Grant No. 15-13436S) for financial support.
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Drchal, V., Turek, I. & Kudrnovský, J. Ab Initio Theory of the Gilbert Damping in Random Ferromagnetic Alloys. J Supercond Nov Magn 30, 1669–1672 (2017). https://doi.org/10.1007/s10948-016-3662-4
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DOI: https://doi.org/10.1007/s10948-016-3662-4