Tailoring Magnetic Exchange Interactions in Ferromagnet-Intercalated MnBi2Te4 Superlattices

TL;DR

This study demonstrates how intercalating ferromagnetic MnTe layers into MnBi2Te4 superlattices allows precise control of magnetic interactions and spin configurations, advancing magnetic topological insulator design for spintronics.

Contribution

It introduces a novel superlattice engineering approach to modulate magnetic exchange interactions in MnBi2Te4-based systems using ferromagnetic intercalation.

Findings

Ferromagnetic MnTe layers mediate anti-ferromagnetic interlayer coupling.

MnTe thickness controls magnetic order strength.

Superlattice periodicity enables tuning of spin configurations.

Abstract

The intrinsic magnetic topological insulator MnBi2Te4 (MBT) has provided a platform for the successful realization of exotic quantum phenomena. To broaden the horizons of MBT-based material systems, we intercalate ferromagnetic MnTe layers to construct the [(MBT)(MnTe)m]N superlattices by molecular beam epitaxy. The effective incorporation of ferromagnetic spacers mediates the anti-ferromagnetic interlayer coupling among the MBT layers through the exchange spring effect at the MBT/MnTe hetero-interfaces. Moreover, the precise control of the MnTe thickness enables the modulation of relative strengths among the constituent magnetic orders, leading to tunable magnetoelectric responses, while the superlattice periodicity serves as an additional tuning parameter to tailor the spin configurations of the synthesized multi-layers. Our results demonstrate the advantages of superlattice engineering for optimizing the magnetic interactions in MBT-family systems, and the ferromagnet-intercalated strategy opens up new avenues in magnetic topological insulator structural design and spintronic applications.