Enhancing Magnetic Ordering in Cr-doped Bi2Se3 using High-TC Ferrimagnetic Insulator

TL;DR

This study demonstrates that coupling Cr-doped Bi2Se3 topological insulators with a high-TC ferrimagnetic insulator enhances magnetic ordering, achieving a Curie temperature of 50 K through the proximity effect, revealing new interaction mechanisms.

Contribution

It introduces a novel approach to enhance magnetic ordering in topological insulators using a high-TC ferrimagnetic insulator via the proximity effect, without disrupting surface states.

Findings

Enhanced Curie temperature of 50 K observed

Increased penetration depth of magnetic influence

Indication of a new interaction mechanism between FMIs and TIs surface

Abstract

We report a study of enhancing the magnetic ordering in a model magnetically doped topological insulator (TI), Bi2-xCrxSe3, via the proximity effect using a high-TC ferrimagnetic insulator Y3Fe5O12. The FMI provides the TI with a source of exchange interaction yet without removing the nontrivial surface state. By performing the elemental specific X-ray magnetic circular dichroism (XMCD) measurements, we have unequivocally observed an enhanced TC of 50 K in this magnetically doped TI/FMI heterostructure. We have also found a larger (6.6 nm at 30 K) but faster decreasing (by 80% from 30 K to 50 K) penetration depth compared to that of diluted ferromagnetic semiconductors (DMSs), which could indicate a novel mechanism for the interaction between FMIs and the nontrivial TIs surface.