Spin injection in the doped bad metal SrTiO_{3}

In this paper, we demonstrate the capability to establish spin-polarized currents in doped SrTiO_{3} (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 La_{0.7}Sr_{0.3}MnO_{3}/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.