Macroscopic Tunneling Probe of Moir\'e Spin Textures in Twisted CrI$_3$

TL;DR

This study investigates the complex magnetic textures in twisted bilayer CrI$_3$ using tunneling magnetoresistance, revealing two distinct non-volatile spin states that can be manipulated with magnetic fields, advancing understanding of moiré spintronics.

Contribution

It provides the first detailed experimental and micromagnetic analysis of moiré-induced spin textures in twisted CrI$_3$, demonstrating controllable non-volatile magnetic states.

Findings

Identification of two distinct non-volatile spin textures at ~1° twist angle.

Demonstration of magnetic field-controlled switching of tunneling resistance.

Observation of hysteretic and anisotropic magnetic state evolution.

Abstract

Various noncollinear spin textures and magnetic phases have been predicted in twisted two-dimensional CrI$_3$ due to competing ferromagnetic (FM) and antiferromagnetic (AFM) interlayer exchange from moir\'e stacking - with potential spintronic applications even when the underlying material possesses a negligible Dzyaloshinskii-Moriya or dipole-dipole interaction. Recent measurements have shown evidence of coexisting FM and AFM layer order in small-twist-angle CrI$_3$ bilayers and double bilayers. Yet, the nature of the magnetic textures remains unresolved and possibilities for their manipulation and electrical readout are unexplored. Here, we use tunneling magnetoresistance to investigate the collective spin states of twisted double-bilayer CrI$_3$ under both out-of-plane and in-plane magnetic fields together with detailed micromagnetic simulations of domain dynamics based on magnetic circular dichroism. Our results capture hysteretic and anisotropic field evolutions of the magnetic states and we further uncover two distinct non-volatile spin textures (out-of-plane and in-plane domains) at $\approx$ 1{\deg} twist angle, with a different global tunneling resistance that can be switched by magnetic field.