Tailored tunnel magnetoresistance response in three ultrathin chromium trihalides

TL;DR

This study compares tunnel magnetoresistance (TMR) in ultrathin chromium trihalides, revealing how material properties and conditions can be tuned to optimize TMR responses near magnetic transition temperatures.

Contribution

It provides a comparative analysis of TMR in all three chromium trihalides, demonstrating how to tailor the TMR response through sample thickness and biasing.

Findings

TMR varies with material and temperature.

Field-induced exchange coupling enhances TMR near transition temperatures.

TMR can be maximized by adjusting experimental conditions.

Abstract

Materials that demonstrate large magnetoresistance have attracted significant interest for many decades. Recently, extremely large tunnel magnetoresistance (TMR) has been reported by several groups across ultrathin CrI$_3$ by exploiting the weak antiferromagnetic coupling between adjacent layers. Here, we report a comparative study of TMR in all three chromium trihalides (CrX$_3$, X= Cl, Br, or I) in the two-dimensional limit. As the materials exhibit different transition temperatures and interlayer magnetic ordering in the ground state, tunneling measurements allow for an easy determination of the field-temperature phase diagram for the three systems. By changing sample thickness and biasing conditions, we then demonstrate how to maximize and further tailor the TMR response at different temperatures for each material. In particular, near the magnetic transition temperature, TMR is non-saturating up to the highest fields measured for all three compounds owing to the large, field-induced exchange coupling.