Large Rashba parameter for 4d strongly correlated perovskite oxide SrNbO3 ultrathin films

To elucidate the spin relaxation mechanism of SrNbO3 (SNO) ultrathin films, the transport properties of a series of SNO films with various thicknesses were measured on both sides of the metal insulator transition. The spin orbit scattering time was deduced from the analysis of the magnetoresistance with weak antilocalization theory, and it was found that the spin orbit scattering time was inversely proportional to the momentum scattering time. This result was explained in terms of the DYakonov Perel mechanism, indicative of the dominant Rashba effect. The values of the Rashba parameter were largest in the values reported for other ultrathin films of metallic oxides.