Evidence of Strong Dzyaloshinskii-Moriya Interaction at the Cobalt/Hexagonal Boron Nitride Interface

TL;DR

This study demonstrates a strong Dzyaloshinskii-Moriya interaction at the Co/h-BN interface, comparable to Pt/Co, supporting a Rashba-like origin and enabling skyrmion stabilization at room temperature.

Contribution

It provides experimental evidence of significant DMI at the Co/h-BN interface and explores its enhancement in heterostructures for skyrmion stabilization.

Findings

DMI at Co/h-BN is comparable to Pt/Co.

Strong DMI supports Rashba-like origin.

Skyrmions stabilized at room temperature.

Abstract

The Dzyaloshinskii-Moriya interaction (DMI) and perpendicular magnetic anisotropy (PMA) were measured on four series of Co films (1-2.2 nm thick) grown on Pt or Au and covered with h-BN or Cu. Clean h-BN/Co interfaces were obtained by exfoliating h-BN and transferring it onto the Co film in situ in the ultra-high-vacuum evaporation chamber. By comparing h-BN and Cu-covered samples, the DMI induced by the Co/h-BN interface was extracted and found to be comparable in strength to that of the Pt/Co interface, one of the largest known values. The strong observed DMI despite the weak spin-orbit interaction in h-BN supports a Rashba-like origin in agreement with recent theoretical results. Upon combination of it with Pt/Co in Pt/Co/h-BN heterostructures, even stronger PMA and DMI are found which stabilizes skyrmions at room temperature and a low magnetic field.