Recent progress in anomalous Nernst effect in magnetic Heusler alloys

Abstract

The worldwide expedition for sustainable energy resources and clean electrical energy harvesting from renewable thermal energy has led to the dawn of spincaloritronics, a vast field that amalgamates spin transport and thermoelectricity. The anomalous Nernst effect (ANE) is one of the many branches of spincaloritronics which is usually observed in metallic and semiconducting magnetic materials. This effect makes use of the spin degree of freedom of an electron in those materials in addition to its charge to harvest electrical energy from renewable thermal energy. The ANE has recently attracted the attention of the spincaloritronics community as ANE-based thermoelectric generators have demonstrated superior performance and advantages over conventional Seebeck effect-based thermoelectric generators. Magnetic Heusler alloys with high Curie temperatures and large spin polarizations along with tunable magnetic and magnetotransport properties have shown emergent potential for room temperature ANE-based thermopile device applications. Particularly, topological Heusler alloys, such as Co2MnGa, which exhibits large intrinsic Berry curvatures at the Fermi energy, have demonstrated the largest anomalous Nernst conductivities reported to date at room temperature amongst all conventional magnetic materials. Unlike prior reviews, which have focused on specific subclasses, our article offers a broader and more inclusive survey. In this article, we aim to review recent progress in the study of the ANE across a broad spectrum of magnetic Heusler alloys, including full, quaternary, and half Heusler compounds, and explore their potential for room-temperature ANE-based thermoelectric device applications as well as propose potential strategies for enhancing ANE in these magnetic Heusler alloys.