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Phonon-driven spin current generation in ferromagnetic thin films

Event Details

Event Dates: 

Tuesday, May 1, 2012 - 11:30am

Speaker Name(s): 

Mathias Weiler

Speaker Affiliation(s): 

Walther-Meißner-Institut Bayerische Akademie der Wissenschaften Garching, Germany
Seminar Type/Subject

Event Details & Abstract: 

Future spintronic devices may take advantage of the electron’s spin degree of freedom inaddition to its charge. In these devices, pure spin currents, i.e., the directed flow of angularmomentum, replace the conventionally used charge currents and give access to newfunctionality. In this talk I will give an introduction to the generation and detection of spincurrents in ferromagnet/normal metal bilayers and then present our recent experimentalresults on spin pumping by acoustic and spatially confined thermal phonons. I will show thatthe resonant magnetoelastic interaction of a GHz sound wave and a ferromagnetic thin filmcan be used to generate a spin current [1]. Furthermore, I will demonstrate that local thermalgradients in insulating ferromagnetic thin films give rise to local, bipolar spin currents whichestablishes the imaging of magnetic texture by the local spin Seebeck effect [2].[1] Weiler et al., ArXiv 1110.1187 (2012, Phys. Rev. Lett., in press)[2] Weiler et al., Phys. Rev. Lett. 108, 106602 (2012)Mathias Weiler studied physics at the Carl von Ossietzky University Oldenburg and theTechnical University Munich where he received his Diploma degree in physics in 2007. Hethen joined the Walther-Meißner-Institut for low-temperature research in Garching. At theWMI he is a research staff member and has been working on the experimental investigationof magnon-phonon interaction phenomena in ferromagnetic thin films for spin currentgeneration. Mr. Weiler just submitted his PhD thesis on acoustic and thermal spin pumping.