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 42.3: Hauptvortrag

Donnerstag, 29. März 2012, 16:00–16:30, EB 301

Seebeck spin tunneling into silicon — •Ron Jansen — National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan.

The combination of thermoelectrics and spintronics offers unique possibilities. On the one hand, it provides a new, spin-based approach to thermoelectric power generation and cooling. On the other hand, it provides a thermal route to create and control the flow of spin in spintronic devices that make functional use of heat and temperature gradients. Here we describe and report the demonstration of Seebeck spin tunneling - a thermally driven spin flow, of purely interfacial nature - generated in a tunnel contact between electrodes of different temperatures. It is shown to be due to the spin dependence of the Seebeck coefficient of a tunnel junction. Thus, Seebeck spin tunneling is the thermoelectric analog of spin-polarized tunneling.

By exploiting this in ferromagnet/oxide/silicon tunnel junctions, we observe a thermal flow of spin angular momentum from the ferromagnet to the silicon without a charge tunnel current. The spin accumulation induced in the silicon scales linearly with heating power and changes sign when the temperature differential is reversed. This thermal spin current can be used by itself, or in combination with electrical spin injection. The results highlight the engineering of heat transport in spintronic devices and enable the (re-)use of heat to increase device efficiency and reduce energy consumption.

J.C. Le Breton, S. Sharma, H. Saito, S. Yuasa and R. Jansen, Nature 475, 82 (2011).