Demonstration of polycrystalline thin film coatings on glass for spin Seebeck energy harvesting

The spin Seebeck effect, a newly discovered phenomena, has been suggested as a potential ‘game changer’ for thermoelectric technology due to the possibility of separating the electric and thermal conductivities. This is due to a completely different device architecture where, instead of an arrangement of p- and n-type pillars between two ceramic blocks, a thermopile could be deposited directly onto a magnetic film of interest. Here we report on the spin Seebeck effect in polycrystalline Fe3O4 :Pt bilayers deposited onto amorphous glass substrates with a view for economically viable energy harvesting. Crucially, these films exhibit large coercive fields (197 Oe) and retain 75% of saturation magnetisation, in conjunction with energy conversion comparable to epitaxially grown films. This demonstrates the potential of this technology for widespread application in harvesting waste heat for electricity.