Relaxation of transport properties in electron-doped SrTiO3

We electron-dope single crystal samples of SrTiO3 by exposing them to Ar+ irradiation and observe carrier mobility similar in its magnitude and temperature dependence to the carrier mobility in other electron-doped SrTiO3 systems. We find that some transport properties are time dependent. In particular, the sheet resistance increases with time at a temperature-dependent rate, suggesting an activation barrier on the order of 1eV. We attribute the relaxation effects to diffusion of oxygen vacancies—a process with energy barrier similar to the observed activation energy.