Proximity effect between a topological insulator and a magnetic insulator with large perpendicular anisotropy

TL;DR

This study demonstrates the epitaxial growth of Bi2Se3 topological insulator films on a magnetic insulator BaFe12O19, revealing magnetic proximity effects that suppress weak antilocalization, with implications for spintronic applications.

Contribution

First demonstration of epitaxial Bi2Se3 on a magnetic insulator with large perpendicular anisotropy, showing magnetic proximity effects on topological surface states.

Findings

Bi2Se3 films grown on BaFe12O19 exhibit altered magnetoresistance behavior.

Suppression of weak antilocalization due to magnetic interactions at the interface.

Magnetic proximity effect influences quantum interference in topological insulators.

Abstract

We report that thin films of a prototype topological insulator, Bi$_{2}$Se$_{3}$, can be epitaxially grown onto the (0001) surface of BaFe$_{12}$O$_{19}$(BaM), a magnetic insulator with high Curie temperature and large perpendicular anisotropy. In the Bi$_2$Se$_3$ thin films grown on non-magnetic substrates, classic weak antilocalization (WAL) is manifested as cusp-shaped positive magnetoresistance (MR) in perpendicular magnetic fields and parabola-shaped positive MR in parallel fields, whereas in Bi$_{2}$Se$_{3}$/BaM heterostructures the low field MR is parabola-shaped, which is positive in perpendicular fields and negative in parallel fields. The magnetic field and temperature dependence of the MR is explained as a consequence of the suppression of WAL due to strong magnetic interactions at the Bi$_{2}$Se$_{3}$/BaM interface.