2022, Martini, Mickey, Reichlova, Helena, Lee, Yejin, Dusíková, Dominika, Zemen, Jan, Nielsch, Kornelius, Thomas, Andy

We present an analysis of magneto-thermal transport data in IrMn/FeCo bilayers based on the Mott relation and report an enhancement of the Nernst response in the vicinity of the blocking temperature. We measure all four transport coefficients of the longitudinal resistivity, anomalous Hall resistivity, Seebeck effect, and anomalous Nernst effect, and we show a deviation arising around the blocking temperature between the measured Nernst coefficient and the one calculated using the Mott rule. We attribute this discrepancy to spin fluctuations at the antiferromagnet/ferromagnet interface near the blocking temperature. The latter is estimated by magnetometry and magneto-transport measurements.

2020, Park, G.-H., Reichlova, H., Schlitz, R., Lammel, M., Markou, A., Swekis, P., Ritzinger, P., Kriegner, D., Noky, J., Gayles, J., Sun, Y., Felser, C., Nielsch, K., Goennenwein, S.T.B., Thomas, A.

We report a robust anomalous Nernst effect in Co2MnGa thin films in the thickness regime between 20 and 50 nm. The anomalous Nernst coefficient varied in the range of -2.0 to -3.0 μV/K at 300 K. We demonstrate that the anomalous Hall and Nernst coefficients exhibit similar behavior and fulfill the Mott relation. We simultaneously measure all four transport coefficients of the longitudinal resistivity, transversal resistivity, Seebeck coefficient, and anomalous Nernst coefficient. We connect the values of the measured and calculated Nernst conductivity by using the remaining three magnetothermal transport coefficients, where the Mott relation is still valid. The intrinsic Berry curvature dominates the transport due to the relation between the longitudinal and transversal transport. Therefore, we conclude that the Mott relationship is applicable to describe the magnetothermoelectric transport in Weyl semimetal Co2MnGa as a function of film thickness.