Electrostatic tuning of magnetism at the conducting (111) (La0.3Sr0.7)(Al0.65Ta0.35)/SrTiO3 interface

We present measurements of the low temperature electrical transport properties of the two dimensional carrier gas that forms at the interface of (111) (La0.3Sr0.7)(Al0.65Ta0.35)/SrTiO3 as a function of applied back gate voltage, Vg. As is found in (111) LaAlO3/SrTiO3 interfaces, the low-field Hall coefficient is electron-like but shows a sharp reduction in magnitude below V g ∼ 20 V, indicating the presence of hole-like carriers in the system. This same value of Vg correlates approximately with the gate voltage below which the magnetoresistance evolves from nonhysteretic to hysteretic behavior at millikelvin temperatures, signaling the onset of magnetic order in the system. We believe our results can provide insight into the mechanism of magnetism in SrTiO3 based systems.