Dependence of the inverse spin Hall effect in Sr(NbxTi1−x)O3 on the Nb concentration

Abstract We measured the spin rectification effect and the inverse spin Hall effect in Nb-doped SrTiO 3 by pumping the spins from the ferromagnetic thin films into SrTiO 3 . The spin injection is increased when the doping level is increased. However, the spin to charge conversion efficiency which is measured by the spin Hall angle decreases when Nb concentration is more than ∼ 0.02 wt%. We argued that it is because that the electrons contributed to the inverse spin Hall effect are from the d − orbitals of Nb instead of Ti beyond this concentration. Our work points to the importance of orbital occupations in the (inverse) spin Hall effect. We may explore controllable spin and charge interconversion in oxide spintronics.