Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Magnetocaloric Effects (joint session MA/TT)

TT 38.9: Vortrag

Dienstag, 13. März 2018, 11:45–12:00, EB 407

Anomalous Nernst effect in carbon doped Mn₅Ge₃ and Mn₅Si₃ thin films — •Sasmita Srichandan, Sihao Deng, and Christoph Sürgers — Karlsruhe Institute of Technology, Physikalisches Institut, PO Box 6980, 76049 Karlsruhe, Germany

Carbon doped Mn₅Ge₃ shows enhanced magnetic properties compared to pure Mn₅Ge₃ which makes Mn₅Ge₃C_x suitable for spintronics applications. The magnetotransport properties of ferromagnetic Mn₅Ge₃, Mn₅Ge₃C_0.8 and Mn₅Si₃C_0.8 systems have been previously investigated [1]. In this present work, the thermal-magnetotransport properties, in particular the anomalous Nernst effect (ANE), have been experimentally investigated in thin films of Mn₅Ge₃C_0.8, Mn₅Si₃C_0.8 and Mn₅Ge₃ on Ge (111). The ANE coefficients for all the films show the same positive sign at high temperatures until at about 100 K the sign changes to negative for Mn₅Ge₃C_0.8 and Mn₅Ge₃ films but not for Mn₅Si₃C_0.8 film. This behavior follows the same change of sign behavior previously observed in the anisotropic magnetoresistance ratio and ordinary Hall coefficient for these films. The change of sign of the ANE is the direct consequence of the Mott relation in our ferromagnetic films [2] even if the sign of the anomalous Hall coefficient remains unchanged. In addition, a possible contribution from the spin Seebeck effect to the transverse thermo-voltage has been addressed.

[1] C. Sürgers et al. Phys. Rev. B 90, 104421(2014)

[2] T. Miyasato et al. Phys. Rev. Lett. 99, 086602(2007)