Electrostatic tuning of magnetism at the conducting (111) (La$_{0.3}$Sr$_{0.7}$)(Al$_{0.65}$Ta$_{0.35}$)/SrTiO$_3$ interface

摘要

We present measurements of the low temperature electrical transportproperties of the two dimensional carrier gas that forms at the interface of$(111)$ (La$_{0.3}$Sr$_{0.7}$)(Al$_{0.65}$Ta$_{0.35}$)/SrTiO$_3$ (LSAT/STO) asa function of applied back gate voltage, $V_g$. As is found in (111)LaAlO$_3$/SrTiO$_3$ interfaces, the low-field Hall coefficient iselectron-like, but shows a sharp reduction in magnitude below $V_g \sim$ 20 V,indicating the presence of hole-like carriers in the system. This same value of$V_g$ correlates approximately with the gate voltage below which themagnetoresistance evolves from nonhysteretic to hysteretic behavior atmillikelvin temperatures, signaling the onset of magnetic order in the system.We believe our results can provide insight into the mechanism of magnetism inSrTiO$_3$ based systems.