Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 50: Spincaloric Transport (jointly with TT)
MA 50.4: Talk
Thursday, March 23, 2017, 10:15–10:30, HSZ 403
Interface dependent magnon mode coupling in insulating ferrimagnets — •Joel Cramer1,2, Er-Jia Guo1,3, Andreas Kehlberger1, Gerhard Jakob1, and Mathias Kläui1,2 — 1Institut für Physik, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany — 2Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany — 3Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, 37830 TN, USA
One of the contemporary challenges of magnon spintronics is the profound understanding of magnon mode dependent transport and interface transmission. To approach this problem, we present temperature dependent spin Seebeck (SSE) measurements in uncompensated (yttrium iron garnet (YIG) [1]) and compensated (e.g. gadolinium iron garnet (GdIG) [2]) insulating ferrimagnets. In YIG, a giant enhancement of the SSE amplitude is observed at low temperatures. Despite the bulk origin of the spin current generation, the temperature dependence varies with the used heavy metal (HM) detection layer. Systematic studies including transmission electron microscopy (TEM) reveal that this effect is due to the altered atomistic composition of YIG at the interface. In compensated ferrimagnets, the opposite contribution of distinct magnon modes leads to a sign change of the spin current at low temperatures [3]. We show that different HM layers as well as a modified GdIG surface morphology result in varied interface couplings of these modes, expressed by a temperature shift of the sign change. [1] Guo et al., Phys. Rev. X 3, 031012 (2016) [2] Cramer et al., (under review) [3] Geprägs et al., Nature Comm. 7, 10452 (2016)