Intrinsic damping phenomena from quantum to classical magnets: An ab initio study of Gilbert damping in a Pt/Co bilayer

Article

关键词: TOTAL-ENERGY CALCULATIONS;    AUGMENTED-WAVE METHOD;    BASIS-SET;    METALS;    RELAXATION;    LAYER;   

DOI  :  10.1103/PhysRevB.96.214421

来源: SCIE

【 摘 要 】

A fully quantum-mechanical description of the precessional damping of a Pt/Co bilayer is presented in the framework of the Keldysh Green's function approach using ab initio electronic structure calculations. In contrast to previous calculations of classical Gilbert damping (alpha(GD)), we demonstrate that alpha(GD) in the quantum case does not diverge in the ballistic regime due to the finite size of the total spin S. In the limit of S -> infinity we show that the formalism recovers the torque correlation expression for alpha(GD) which we decompose into spin-pumping and spin-orbital torque correlation contributions. The formalism is generalized to take into account a self-consistently determined dephasing mechanism which preserves the conservation laws and allows the investigation of the effect of disorder. The dependence of alpha(GD) on Pt thickness and disorder strength is calculated, and the spin-diffusion length of Pt and the spin mixing conductance of the bilayer are determined and compared with experiments.

【 授权许可】

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