title: Amplification of spin waves by thermal spin-transfer torque.
abstract: We observe amplification of spin-wave packets propagating along a film of single-crystal yttrium iron garnet subject to a transverse temperature gradient. The spin waves are excited and detected with standard techniques used in magnetostatic microwave delay lines in the 1-2 GHz frequency range. The amplification is attributed to the action of a thermal spin-transfer torque acting on the magnetization that opposes the relaxation and which is created by spin currents generated through the spin-Seebeck effect. The experimental data are interpreted with a spin-wave model that gives an amplification gain in very good agreement with the data.
authors.affiliation: Departamento de Física, Universidade Federal de Pernambuco, Recife, PE 50670-901, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Padrón-Hernández
authors.forename: A
authors.initials: A
authors.lastname: Azevedo
authors.forename: S M
authors.initials: SM
authors.lastname: Rezende