Role of stacking defects on the magnetic behavior of CrCl$_3$

TL;DR

This study investigates how stacking defects in CrCl$_3$ influence its magnetic properties, revealing that structural imperfections lead to anomalous magnetic behavior and domain formation near the Néel temperature.

Contribution

It provides new insights into the role of stacking defects in modulating the magnetic behavior of CrCl$_3$, linking structural imperfections to magnetic anomalies.

Findings

Stacking defects cause hysteresis and enhanced magnetization above 14 K.

M-type stacking defects are linked to anomalies in magnetization and phase transitions.

Powder samples show stronger anomalous magnetic behavior.

Abstract

In the study of van der Waals-layered magnetic materials, the properties of CrCl$_3$ continue to attract attention. This compound is reported to undergo antiferromagnetic (AFM) ordering below $\sim$14 K, with a ferromagneticlike region proposed to exist between 14 and 17 K. Ideally, the crystal structure is rhombohedral (R) below $\sim$235 K, separated from a higher-temperature monoclinic (M) phase by a layer-sliding structural phase transition. However, the structural transition is often inhibited even in bulk single crystals, allowing M-type layer stacking, reported to have a tenfold greater interlayer magnetic coupling than R-type stacking, to be present at low temperature. To clarify the effect of stacking defects on CrCl$_3$, we report magnetization measurements on samples of varying crystalline quality. At low applied magnetic field, some crystals predominantly show the $T_N=14$ K peak, but other crystals show hysteretic behavior and a magnetization enhancement at a slightly higher temperature ($14 < T \lesssim 17$ K.) Samples with anomalous behavior exhibit a transition around $\sim$2 T in isothermal magnetization-field data, providing evidence that M-type stacking defects are the source of these anomalies. Ground powder samples are especially likely to show strongly anomalous behavior. We suggest that the anomalous behavior arises from few-layer magnetic domains that form just above $T_N$ in an environment of mixed interlayer magnetic coupling strength. We argue that the influence of M-type stacking boundaries on sublattice magnetization is already observable in reported neutron scattering data, and may be responsible for a certain feature in reported specific heat data.