Magnetic proximity effect in the heterostructures of topological insulators and SrRuO3

Abstract

Introducing magnetic order into a topological insulator via the magnetic proximity effect can break the time-reversal symmetry of the topological surface states, resulting in a variety of exotic physical phenomena that are expected to be applied in spintronic devices. However, in the topological insulator/ferromagnet heterostructures obtained so far, the interfacial hybridization is too weak and difficult to induce sufficiently strong magnetism in the topological insulator. In this work, we investigate the electrical transport properties of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures and demonstrate the presence of the magnetic proximity effect in them. The Curie temperature of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures was found to be increased by about 25 K. The coercive field was suppressed in the magnetoresistance; the Hall curves of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures exhibited different orientations and appeared non-linear behavior at high fields, and the anisotropic magnetoresistance changed from twofold rotational symmetry to quadruple symmetry. These provide direct evidence for the emergence of the magnetic proximity effect. This work will help to study the magnetic proximity effect in the topological insulators and paves the way for spintronic devices in the future.