Shirin Mozaffari, UT-Austin

"Spin-Orbit Interaction and Kondo Scattering at the PrAlO3/SrTiO3 Interface: Effects of Oxygen Content"

Abstract: The broken translational symmetry at an interface between complex metal oxides gives rise to a number of remarkable phenomena with rich physics, such as superconductivity, metal-insulator transitions, and giant magnetoresistance. These phenomena can be entirely different from those innate to the constituent materials. A recent example of such interface phenomena is the formation of the two-dimensional electron gas (2DEG) at the interface of LaAlO3 (LAO) and TiO2- terminated SrTiO3 (STO). Despite that LAO and STO are both insulators and non-magnetic, their interface is found to be conductive, superconductive, and ferromagnetic, which all are the results of electronic reconstruction at the interface.

We examined, in detail, the effects of oxygen content on the electrical and magnetic properties of PrAlO3 (PAO) on STO. Among the aluminates, PAO has the closest lattice constant to LAO, and thus this helps to lessen the effect of strain as much as possible. Also, the effective magnetic moment of the Pr3+ f electron states is 3.6 Bohr magnetons, due to often hybridized, while closed shell La3+ is diamagnetic, thus this rare-earth substitution can lead to magnetic properties in an aluminate structure. PAO is known to be paramagnetic in bulk and has mostly been studied for its structural transitions below room temperature which are absent in LAO. The effects that will be discussed will be Kondo scattering and strong spin-orbit interaction.