Rashba-type Dzyaloshinskii-Moriya interaction, perpendicular magnetic anisotropy and skyrmion states at 2D materials/Co interfaces

TL;DR

This study reveals strong Dzyaloshinskii-Moriya interaction and perpendicular magnetic anisotropy at h-BN/Co interfaces, enabling skyrmion formation and advancing 2D materials' integration into spin-orbitronic devices.

Contribution

It demonstrates the enhancement of DMI and PMA at h-BN/Co interfaces compared to graphene/Co, and shows stable skyrmion formation over a range of Co thicknesses and temperatures.

Findings

DMI increases with Co thickness at h-BN/Co interfaces

Skyrmions form under small external fields up to 100 K

DMI at h-BN/Co is an order of magnitude larger than at graphene/Co

Abstract

We report a significant Dzyaloshinskii-Moriya interaction (DMI) and perpendicular magnetic anisotropy (PMA) at interfaces comprising hexagonal boron nitride (h-BN) and Co. By comparing the behavior of these phenomena at graphene/Co and h-BN/Co interfaces, it is found that the DMI in latter increases as a function of Co thickness and beyond three monolayers stabilizes with one order of magnitude larger values compared to those at graphene/Co, where the DMI shows opposite decreasing behavior. At the same time, the PMA for both systems shows similar trends with larger values for graphene/Co and no significant variations for all thickness ranges of Co. Furthermore, using micromagnetic simulations we demonstrate that such significant DMI and PMA values remaining stable over large range of Co thickness give rise to formation of skyrmions with small applied external fields in the range of 200-250 mT up to 100 K temperatures. These findings open up further possibilities towards integrating two-dimensional (2D) materials in spin-orbitronics devices.