Observation of Spin Nernst effect in Platinum

Abstract: Central focus of spintronics is concentrated on generation of pure spin current and associated spin torque. Pure spin current can be generated by spin Hall effect in heavy metals by passing charge current. By spin Seebeck effect pure spin current can also be generated in ferromagnet. In this work we experimentally demonstrate that if heavy metals like Platinum with high spin orbit coupling carry heat current it can convert it into spin current due to relativistic spin orbit interaction. This conversion of heat current into spin current in non magnet is equivalent of thermally driven spin Hall effect or it is known as spin Nernst effect. We observed spin Nernst effect in Ni/Pt bi-layer experimentally and we confirm that when Pt is replaced by low spin orbit material like Al spin Nernst effect significantly reduces. So we have detected spin Nernst effect unambiguously and compare its strength with electrical spin Hall effect.