Field-induced antiferromagnetic correlations in a nanopatterned van der Waals ferromagnet: a potential artificial spin ice

TL;DR

This study demonstrates that nanopatterned 2D van der Waals ferromagnets can exhibit tunable antiferromagnetic correlations, enabling the creation of artificial spin-ice systems with complex magnetic interactions through precise nano-patterning and control.

Contribution

It introduces a method to induce and control antiferromagnetic correlations in nanopatterned 2D vdW magnets, advancing artificial spin-ice research.

Findings

Pristine CrGeTe3 flakes as small as 150x150x60 nm3 show tunable dipole interactions.

Spatial distribution controls the crossover from non-interacting to anticorrelated islands.

Nano-patterned magnets can generate complex, exotic spin configurations.

Abstract

Nano-patterned magnetic materials have opened new venues on the investigation of strongly correlated phenomena including artificial spin-ice systems, geometric frustration, magnetic monopoles, for technologically important applications such as reconfigurable ferromagnetism. With the advent of atomically thin two-dimensional (2D) van der Waals (vdW) magnets a pertinent question is whether such compounds could make their way into this realm where interactions can be tailored so that unconventional states of matter could be assessed. Here we show that square islands of CrGeTe3 vdW ferromagnets distributed in a grid manifest antiferromagnetic correlations, essential to enable frustration resulting in an artificial spin-ice. By using a combination of SQUID-on-tip microscopy, focused ion beam lithography, and atomistic spin dynamic simulations, we show that pristine, isolated CGT flakes as small as 150*150*60 nm3 have tunable dipole-dipole interactions, which can be precisely controlled by their lateral spacing. There is a crossover between non-interacting islands and significant inter-island anticorrelation depending how they are spatially distributed allowing the creation of complex magnetic patterns not observable at the isolated flakes. Our findings suggest that the cross-talk between the nano-patterned magnets can be explored in the generation of even more complex spin configurations where exotic interactions may be manipulated in an unprecedent way.