Regensburg 2019 – scientific programme

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MA: Fachverband Magnetismus

MA 12: Spincaloric transport

MA 12.3: Talk

Monday, April 1, 2019, 17:45–18:00, H53

Anomalous Nernst effect in magnetic tunnel junctions: A concept for direction dependent temperature sensing — Ulrike Martens¹, Torsten Huebner², Henning Ulrichs³, Oliver Reimer², Timo Kuschel², Ronnie Tamming⁴, Chia-Lin Chang⁴, Raanan Tobey⁴, Andy Thomas⁵, Markus Münzenberg¹, and •Jakob Walowski¹ — ¹Universität Greifswald, Greifswald, Germany — ²Bielefeld University, Bielefeld, Germany — ³Universität Göttingen, Göttingen, Germany — ⁴University of Groningen, Groningen, The Netherlands — ⁵IFW Dresden, Institute for Metallic Materials, Dresden, Germany

CoFeB/MgO based magnetic tunnel junctions (MTJs) exhibit a large tunnel magnetoresistence effect due to a high spin polarization given by the material combination. This enables information storage based on the magnetization state. Replacing the voltage as a driving force for the spin polarized currents by temperature gradients opens up new functionalities for these devices. By applying a homogeneous temperature gradient across the tunnel barrier, the tunneling magneto-Seebeck effect (TMS) can be used as a readout method, because the generated voltage is magnetization dependent. Inhomogeneous temperature gradients generate additional thermomagnetic effects, which have an impact on the TMS. Those effects, e.g. the anomalous Nernst effect (ANE), can be extracted by systematically changing the temperature gradient direction and measuring the TMS. We demonstrate, that analyzing the ANE with respect to the temperature gradient directions, allows for direction dependent temperature sensing.