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 1 eV. We attribute the relaxation effects to diffusion of oxygen vacancies-a process with energy barrier similar to the observed activation energy.