Paper detail

Enhancement of YIG$|$Pt spin conductance by local Joule annealing

We report that Joule heating can be used to enhance the interfacial spin conductivity between a metal and an oxide. We observe that local annealing of the interface at about 550\,K by injecting large current densities ($>10^{12}\text{A/m}^{2}$) into a pristine 7\,nm thick Pt nanostrip evaporated on top of yttrium iron garnet (YIG), can improve the spin transmission up to a factor 3: a result of particular interest for interfacing ultra thin garnet films where strong chemical etching of the surface has to be avoided. The effect is confirmed by different methods: spin Hall magnetoresistance, spin pumping and non-local spin transport. We use it to study the influence of the YIG$|$Pt coupling on the non-linear spin transport properties. We find that the cross-over current from a linear to a non-linear spin transport regime is independent of this coupling, suggesting that the behavior of pure spin currents circulating in the dielectric are mostly governed by the physical properties of the bare YIG film beside the Pt nanostrip.