Thermal spin transport and applications

Spin caloritronics, exploiting the interaction between spin with heat currents, offers a promising path to further reduction in both the size and power consumption of solid state devices. Despite recent observations of spin dependent thermal transport by several groups, the underlying physical mechanism remains unsettled.^1-3 Our study has demonstrated the profound effect of substrate on the spin-dependent thermal transport by patterned ferromagnetic thin films.⁴ This unexpected behavior is due to an out-of-plane temperature gradient imposed by the thermal conduction through the substrate, resulting in a mixture of anomalous Nernst effects (ANE) and spin Seebeck effect (SSE)^1-3. Only with substrate-free sample have we determined the intrinsic spin-dependent thermal transport with characteristics and field sensitivity similar to those of anisotropic magnetoresistance (AMR) effect and planer Hall effect (PHE).⁴ These effects are sensitive to magnetic fields, encouraging for future applications such as spin thermoelectric coating, and sensors.