Extraordinary magnetoresistance in high-mobility doped SrTiO₃ thin films

Magnetoresistive sensors are widely used to detect magnetic fields by measuring changes in electrical resistance. One such effect, extraordinary magnetoresistance (EMR), arises from the geometry of hybrid structures consisting of high-mobility semiconductors and highly conductive metals. While most previous EMR studies have focused on III-V semiconductors and 2D materials, there has been no demonstration in oxides. Here, we demonstrate both symmetric and asymmetric EMR in high-quality La-doped SrTiO₃ thin films (µ > 52,000 cm²V^-1s^-1 at 1.8 K) using hybrid molecular beam epitaxy. The measured resistance of the oxide/metal EMR devices changes around 9000% when applying 9 T at 1.8 K, which exceeds the intrinsic magnetoresistance of SrTiO₃ by a factor of 40. Finite element simulations of current flow and MR align well with experimental data, validating the design principles. These results establish the potential of complex oxides for low-temperature EMR sensors and open opportunities for integrating oxide heterostructures in future magnetoelectronic devices.