title: Direct measurement of magnon temperature: new insight into magnon-phonon coupling in magnetic insulators.
abstract: We present spatially resolved measurements of the magnon temperature in a magnetic insulator subject to a thermal gradient. Our data reveal an unexpectedly close correspondence between the spatial dependencies of the exchange magnon and phonon temperatures. These results indicate that if--as is currently thought--the transverse spin Seebeck effect is caused by a temperature difference between the magnon and phonon baths, it must be the case that the magnon temperature is spectrally nonuniform and that the effect is driven by the sparsely populated dipolar region of the magnon spectrum.
authors.affiliation: Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany and Graduate School Materials Science in Mainz, Gottlieb-Daimer-Strasse 47, 67663 Kaiserslautern, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Agrawal
authors.affiliation: Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: V I
authors.initials: VI
authors.lastname: Vasyuchka
authors.affiliation: Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: A A
authors.initials: AA
authors.lastname: Serga
authors.affiliation: Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom.
authors.forename: A D
authors.initials: AD
authors.lastname: Karenowska
authors.affiliation: Faculty of Radiophysics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine.
authors.forename: G A
authors.initials: GA
authors.lastname: Melkov
authors.affiliation: Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Hillebrands