Large Linear Magnetoresistance of High‐Mobility 2D Electron System at Nonisostructural γ‐Al2O3/SrTiO3 Heterointerfaces.

Materials with a large linear magnetoresistance (MR) are great candidates for magnetic sensors, but rarity boosts investigations for exploring this MR in material physics. 2D electron system (2DES) formed at the nonisostructural heterointerfaces between γ‐Al2O3 (GAO) and SrTiO3 (STO) provides plenty of intriguing or even superior emergent properties compared with the conventional isomorphic all‐perovskite counterparts. Herein, a large MR exceeding 2000% in magnitude at the magnetic GAO/STO heterointerfaces with a high carrier mobility of 30 000 cm2 V−1 s−1 at low temperature is demonstrated. In contrast to the quadratic dependence on the magnetic field of the conventional oxide 2DES, MR in GAO/STO is linear and nonsaturating at high fields, which is stemmed from the magnetic inhomogeneities‐induced inhomogeneous conductivities. In addition, weak antilocalization effect gives rise to an extra quantum correction to the MR in low‐field region. Furthermore, a general qualitative picture of MR proportional to the mobility is established. These findings reveal the nonisostructural GAO/STO heterointerface is of great promise in magnetic sensor‐based practical memory applications and transistor designs. [ABSTRACT FROM AUTHOR]