Spin injection in the doped bad metal SrTiO3

In this paper, we demonstrate the capability to establish spin-polarized currents in doped SrTiO3 (STO). The results are based on the study of charge and spin transport in STO layers doped by the reversible electromigration of oxygen atoms in resistive-switching La0.7Sr0.3MnO3/STO/Co vertical stacks. The formation of oxygen vacancies inside STO results in a metallic conductivity at temperatures <200-250 K, above which a transition to an insulatinglike behavior is detected. A detailed theoretical analysis shows that the behavior of the metallic phase in our samples corresponds to the well-known state of the thermodynamically doped STO featuring the so-called bad metal behavior. Thus, our findings introduce this class of unconventional materials as valuable candidates for innovative spintronic devices.