Temperature dependence of the anomalous Nernst effect in a Ni-Mn-Ga system*

Ni-Mn-Ga alloys, well-known for showing large magnetic shape memory effect, undergoes various phase transitions upon cooling, sensitive to their compositional variations. In this work, we report a detail investigation of the off-stoichiometric N i_1.95Mn_1.05Ga through various magnetic, electronic, and thermal characterizations. Of particular, anomalous Nernst effect (ANE) studies are presented for the first time in these class of material, revealing that the ANE is very sensitive across the pre-martensitic transition in comparison to other transport measurements. With the ANE being sensitive to changes at the Fermi surface, we infer the link of structural modulations with the modulation of the Fermi surface via its nesting features. Moreover, the large ANE-signal at room temperature and the significant drop across the martensitic transition could also be promising for many spintronics applications.