Spin-orbit interaction and Kondo scattering at the PrAlO₃/SrTiO₃ interface: effects of oxygen content

We report the effects of oxygen pressure during growth ([Formula: see text]) on the electronic and magnetic properties of PrAlO₃ films grown on [Formula: see text]-terminated SrTiO₃ substrates. Resistivity measurements show an increase in the sheet resistance as [Formula: see text] is increased. The saturation of the sheet resistance down to 0.3 K is consistent with Kondo theory for [Formula: see text] torr. Resistivity data fits indicate Kondo temperatures of 16-18 K. For the [Formula: see text] sample, we measured a moderate positive magnetoresistance (MR) due to a strong spin-orbit (SO) interaction at low magnetic fields that evolves into a larger negative MR at high fields due to the Kondo effect. Analysis of the MR data permitted the extraction of the SO interaction critical field for the [Formula: see text] torr interface ([Formula: see text] T). We observed high positive MR for the least oxygenated sample, where a fraction of the n-type carriers are derived from oxygen vacancies and possible cation interdiffusion; for this [Formula: see text] torr sample, Hall effect data indicate a thick conducting layer. Its extremely high MR (∼[Formula: see text]) is attributed to classical behavior due to a distribution of mobilities.