Large anomalous Nernst effect and its bipolarity in the quaternary equiatomic Heusler alloys CrRuXGe ( X=Co and Mn)

Anomalous Nernst effect (ANE)-based thermopiles can be constructed by combining materials with positive and negative ANE coefficients. While most of the magnetic materials show positive ANE, only a limited number of materials exhibit a negative ANE. Furthermore, the majority of the materials showing negative ANE have low Curie temperatures (TC). Here, the authors demonstrate that high-TC quaternary Heusler alloys with large spin polarizations can exhibit both positive and negative ANE coefficients, depending on their chemical compositions, and hence, can be potential candidates for developing efficient room-temperature ANE-based thermopiles.