Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 42: Joint Session "Novel Spincaloritronic Devices: Control of Heat, Charge and Momentum Flow" (jointly with TT), Organization: Markus Münzenberg (Univ. Göttingen), Mathias Weiler (WMI Garching)
MA 42.4: Topical Talk
Donnerstag, 29. März 2012, 16:30–17:00, EB 301
Spin currents in ferromagnetic insulator/normal metal hybrid structures — •Sebastian T.B. Goennenwein1, Franz D. Czeschka1, Johannes Lotze1, Georg Woltersdorf2, Mathias Weiler1, Michael Schreier1, Matthias Althammer1, Matthias Opel1, Hans Huebl1, and Rudolf Gross1 — 1Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany — 2Department of Physics, Universität Regensburg, Germany
In analogy to the well-established charge currents, one can define a pure spin current as the directed flow of spin angular momentum. However, in spite of the conceptual analogy, the properties of charge and spin currents are very different: In contrast to electrical currents, spin currents can flow in electrical insulators, since no charge motion is required for the propagation of angular momentum.
We experimentally study pure spin currents in magnetic insulators, using two complementary approaches. The samples comprise an epitaxial yttrium iron garnet (YIG) thin film – a ferrimagnetic insulator – covered in situ with a thin platinum layer. On the one hand, we use spin pumping in combination with the inverse spin Hall effect to generate and detect pure spin currents across the YIG/Pt interface. The spin mixing conductance derived from these experiments is quantitatively comparable to that of conductive ferromagnet/Pt hybrids. On the other hand, we investigate the local magneto-thermo-galvanic voltages induced in YIG/Pt by a focused, scanning laser beam, and discuss the contribution of spin currents generated by the spin Seebeck effect.
Financial support by DFG SPP 1538 is gratefully acknowledged.