Microscopic theory of magnon-drag electron flow in ferromagnetic metals

Terufumi Yamaguchi, Hiroshi Kohno, Rembert A. Duine

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

Uittreksel

A temperature gradient applied to a ferromagnetic metal induces not only independent flows of electrons and magnons but also drag currents because of their mutual interaction. In this paper, we present a microscopic study of the electron flow induced by the drag due to magnons. The analysis is based on the s-d model, which describes conduction electrons and magnons coupled via the s-d exchange interaction. Magnetic impurities are introduced in the electron subsystem as a source of spin relaxation. The obtained magnon-drag electron current is proportional to the entropy of magnons and to α-β (more precisely, to 1-β/α), where α is the Gilbert damping constant and β is the dissipative spin-transfer torque parameter. This result almost coincides with the previous phenomenological result based on the magnonic spin-motive forces, and consists of spin-transfer and momentum-transfer contributions, but with a slight disagreement in the former. The result is interpreted in terms of the nonequilibrium spin chemical potential generated by nonequilibrium magnons.

TaalEngels
Artikelnummer094425
Aantal pagina's12
TijdschriftPhysical Review B
Volume99
Nummer van het tijdschrift9
DOI's
StatusGepubliceerd - 19 mrt 2019

Vingerafdruk

Ferromagnetic materials
magnons
drag
Drag
Electrons
metals
electrons
Momentum transfer
Chemical potential
Exchange interactions
conduction electrons
Thermal gradients
momentum transfer
torque
temperature gradients
Entropy
Torque
Damping
damping
interactions

Citeer dit

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abstract = "A temperature gradient applied to a ferromagnetic metal induces not only independent flows of electrons and magnons but also drag currents because of their mutual interaction. In this paper, we present a microscopic study of the electron flow induced by the drag due to magnons. The analysis is based on the s-d model, which describes conduction electrons and magnons coupled via the s-d exchange interaction. Magnetic impurities are introduced in the electron subsystem as a source of spin relaxation. The obtained magnon-drag electron current is proportional to the entropy of magnons and to α-β (more precisely, to 1-β/α), where α is the Gilbert damping constant and β is the dissipative spin-transfer torque parameter. This result almost coincides with the previous phenomenological result based on the magnonic spin-motive forces, and consists of spin-transfer and momentum-transfer contributions, but with a slight disagreement in the former. The result is interpreted in terms of the nonequilibrium spin chemical potential generated by nonequilibrium magnons.",
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Microscopic theory of magnon-drag electron flow in ferromagnetic metals. / Yamaguchi, Terufumi; Kohno, Hiroshi; Duine, Rembert A.

In: Physical Review B, Vol. 99, Nr. 9, 094425, 19.03.2019.

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

TY - JOUR

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AU - Yamaguchi,Terufumi

AU - Kohno,Hiroshi

AU - Duine,Rembert A.

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AB - A temperature gradient applied to a ferromagnetic metal induces not only independent flows of electrons and magnons but also drag currents because of their mutual interaction. In this paper, we present a microscopic study of the electron flow induced by the drag due to magnons. The analysis is based on the s-d model, which describes conduction electrons and magnons coupled via the s-d exchange interaction. Magnetic impurities are introduced in the electron subsystem as a source of spin relaxation. The obtained magnon-drag electron current is proportional to the entropy of magnons and to α-β (more precisely, to 1-β/α), where α is the Gilbert damping constant and β is the dissipative spin-transfer torque parameter. This result almost coincides with the previous phenomenological result based on the magnonic spin-motive forces, and consists of spin-transfer and momentum-transfer contributions, but with a slight disagreement in the former. The result is interpreted in terms of the nonequilibrium spin chemical potential generated by nonequilibrium magnons.

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