Influence of epitaxial growth on spin current transmission of NiO films

Yamazaki, Takumi*; Seki, Takeshi*; Kubota, Takahide*; Takanashi, Koki

We report the effect of the epitaxial growth of NiO films on its spin current transmission. Two sample series of Pt/NiO/CoFeB, including epitaxial and polycrystalline NiO, were prepared using different deposition conditions. The spin current transmission of NiO is evaluated using the thermo-spin effects in the trilayers. Epitaxial NiO exhibits a non-monotonic behavior in the NiO thickness dependence of spin current transmission, while this behavior is smeared out in polycrystalline NiO. The non-monotonic behavior implies the presence of multiple spin transport mechanisms, which becomes apparent with epitaxial growth.