Length Scale of the Spin Seebeck Effect

Andreas Kehlberger, Ulrike Ritzmann, Denise Hinzke, Er-Jia Guo, Joel Cramer, Gerhard Jakob, Mehmet C. Onbasli, Dong Hun Kim, Caroline A. Ross, Matthias B. Jungfleisch, Burkard Hillebrands, Ulrich Nowak (+1 others)
2015 Physical Review Letters  
The observation of the spin Seebeck effect in insulators has meant a breakthrough for spin caloritronics due to the unique ability to generate pure spin currents by thermal excitations in insulating systems without moving charge carriers. Since the recent first observation, the underlying mechanism and the origin of the observed signals have been discussed highly controversially. Here we present a characteristic dependence of the longitudinal spin Seebeck effect amplitude on the thickness of
more » ... the thickness of the insulating ferromagnet (YIG). Our measurements show that the observed behavior cannot be explained by any effects originating from the interface, such as magnetic proximity effects in the spin detector (Pt). Comparison to theoretical calculations of thermal magnonic spin currents yields qualitative agreement for the thickness dependence resulting from the finite effective magnon propagation length so that the origin of the effect can be traced to genuine bulk magnonic spin currents ruling out parasitic interface effects.
doi:10.1103/physrevlett.115.096602 pmid:26371671 fatcat:kehkuqhzhjekbcoioiemffxczq