Spacer-layer-tunable magnetism and high-field topological Hall effect in topological insulator heterostructures

TL;DR

This study demonstrates that adjusting spacer-layer thickness in topological insulator heterostructures allows for tunable magnetic phases and robust topological Hall effects at high magnetic fields, advancing spintronic applications.

Contribution

It introduces spacer-layer control as a novel method to manipulate magneto-topological properties in topological insulator heterostructures without altering chemical composition.

Findings

Magnetic phase can be tuned from ferromagnetic to paramagnetic by spacer-layer thickness.

Robust topological Hall effect observed up to 6 T magnetic field.

Spacer-layer control offers a new way to engineer magneto-topological functionalities.

Abstract

Controlling magnetic order in magnetic topological insulators (MTIs) is a key to developing spintronic applications with MTIs, and is commonly achieved by changing the magnetic doping concentration, which inevitably affects spin-orbit-coupling strength and the very topological properties. Here, we demonstrate tunable magnetic properties in topological heterostructures over a wide range, from a ferromagnetic phase with Curie temperature of around 100 K all the way to a paramagnetic phase, while keeping the overall chemical composition the same, by controlling the thickness of non-magnetic spacer layers between two atomically-thin magnetic layers. This work showcases that spacer-layer control is a powerful tool to manipulate magneto-topological functionalities in MTI heterostructures. Furthermore, the interaction between the MTI and the Cr2O3 buffer layers also led to robust topological Hall effect surviving up to a record-high 6 T of magnetic field, shedding light on the critical role of interfacial layers in thin film topological materials.