High-mobility magnetic two-dimensional electron gas with high Curie temperatures at Eu2O3/SrTiO3 interfaces

High-mobility spin-polarized two-dimensional electron gases (2DEGs) hold fundamental importance for the development of next-generation spintronic devices. In this work, we fabricate a high-quality epitaxial Eu2O3/STO (001) heterointerface, which hosts a two-dimensional electron gas exhibiting a high electron mobility of approximately 4.3 × 103 cm2 V−1 s−1 at 2 K. This interface demonstrates robust metallic conductivity, a pronounced Kondo effect, and an observable anomalous Hall effect that persists up to 100 K. Furthermore, magnetic measurements confirm the emergence of ferromagnetic order, which is primarily attributed to the combined effects of the Ti3+ magnetic moments induced by oxygen vacancies on the surface of the STO single crystal and the localized Eu2+ magnetic moments within the thin film. These collective findings support the possible formation of a spin-polarized 2DEG characterized by a high ferromagnetic ordering temperature. Our work underscores the significant potential of Eu-based oxide heterostructures as a promising platform for fundamental research of spin-polarized 2DEG.