Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Spin dependent Transport Phenomena
MA 35.2: Vortrag
Mittwoch, 9. März 2016, 15:15–15:30, H33
Anomalous magnetothermopower in a metallic frustrated antiferromagnet — •Stevan Arsenijević1,2,3, Jong Mok Ok4, Peter Robinson1,2, Saman Ghannadzadeh1,2, Mikhail I. Katsnelson2, Jun Sung Kim4, and Nigel E. Hussey1,2 — 1High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525ED Nijmegen, Netherlands — 2Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, Netherlands — 3Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany — 4Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
We report the temperature T and magnetic field H dependence of the thermopower S of an itinerant triangular antiferromagnet PdCrO2 in high magnetic fields up to 32 T. In the paramagnetic phase, the zero-field thermopower is positive with a value typical of good metals with a high carrier density. In marked contrast with typical metals, however, S decreases rapidly with increasing magnetic field, approaching zero at the maximum field scale for T > 70 K. We argue here that this profound change in the thermoelectric response is due to the strong interaction of the 4d correlated electrons of the Pd ions with the short-range spin correlations of the Cr3+ spins that persist beyond the Néel ordering temperature. Such (chiral) spin correlations are also believed to be responsible for the unconventional anomalous Hall effect that emerges in PdCrO2 at elevated temperatures.