Optimisation of Co2MnSi thin films and multilayers for spin Seebeck devices

The spin Seebeck effect is defined as the generation of a pure spin current (J
_s
) when a magnetised material is subjected to a temperature gradient (ΔT).To detect it, a thin non-magnetic layer [NM] such as Pt, is deposited on top of the material of interest. This converts the spin current, J
_s
, into an observable thermoelectric voltage (VSSE) by way of the Inverse Spin Hall Effect (ISHE). It has been shown that this effect is linearly proportional to ΔT and the magnetisation of the magnetic layer. Experimentally realised in ferromagnetic insulators, the SSE has also been seen in ferromagnetic conductors (FMC) such as Co
₂
MnSi (CMS). We are interested in how this phenomenon might be applied to harvesting waste heat (thermoelectric generators) or spintronics applications (spin current source). CMS has been proposed to exhibit half metallic behaviour at the Fermi Energy (Ef), where theory predicts 100% spin polarisation (SP), which has recently been backed up by spin-resolved spectroscopy work in thin films.