Anomalous Nernst Effect in Epitaxial L10FePd1−xPtx Alloy Films: Berry Curvature and Thermal Spin Current

Abstract

Anomalous Nernst effect in epitaxially grown $L{1}_{0}$-ordered $\mathrm{Fe}\mathrm{Pd}{}_{1\ensuremath{-}x}\mathrm{Pt}{}_{x}$ alloy films is systematically investigated both experimentally and theoretically. It is found that the anomalous Nernst coefficient and anomalous Hall resistivity both increase monotonically with the increase of $\mathrm{Pt}$ composition. By subtracting the Seebeck contribution, the anomalous Nernst conductivity (${\ensuremath{\alpha}}_{xy}^{A}$) is obtained. By comparison with first-principles Berry-phase-theory calculations, it is interesting to find that the anomalous Nernst conductivity is dominated by the intrinsic contribution from heavy metal $\mathrm{Pt}$-$\mathrm{Pd}$ with large spin-orbit coupling strength. Moreover, the first-principles calculations also predict a large spin Nernst counductivity for both $L{1}_{0}$-ordered $\mathrm{Fe}\mathrm{Pd}$ and $\mathrm{Fe}\mathrm{Pt}$. Thus, the present results may shed light in searching materials with large thermally driven Hall and spin currents.