This article is cited in 2 papers

XXIII International Symposium ''Nanophysics and Nanoelectronics'', Nizhny Novgorod, March 11--14, 2019
Magnetism

Spin pumping in a ferromagnetic insulator / normal metal system: a simple quantum-mechanical model

E. A. Karashtin<sup>ab

a</sup> Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhnii Novgorod
^b Lobachevsky State University of Nizhny Novgorod

Abstract: We suggest a simple quantum-mechanical model of the spin pumping effect that appears when the ferromagnetic resonance is excited in a magnetic insulator that has a flat contact with a nonmagnetic metal. The model is based on the solution of Schrodinger equation for conductance electrons in the metal. We show that electron reflection with spin flip at the boundary with the insulator leads to the dc and ac (oscillating with the frequency of microwave field exciting the resonance) spin flow from ferromagnet to insulator. The dc effect is small compared to the ac effect; the small parameter here is the ratio of exchange constant in the ferromagnet to the energy of potential barrier between the metal and insulator which is greater than the Fermi energy. The obtained result agrees to known experimental data. The developed model provides a simple and spectacular insight into the phenomenon roots and allows to make analysis of the effect dependence on the parameters of considered system.

Keywords: spin pumping, insulator, $s$–$d$ exchange, ferromagnetic resonance, spin current.

Received: 15.04.2019
Revised: 22.04.2019
Accepted: 24.04.2019

DOI: 10.21883/FTT.2019.09.48102.05N

 English version: Physics of the Solid State, 2019, 61:9, 1583–1589

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