Magnetic structure determination of rare-earth based, high moment, atomic laminates; potential parent materials for 2D magnets

TL;DR

This study investigates the magnetic properties of rare-earth based atomic laminates, identifying Gd variants as promising candidates for stable 2D high-moment magnetic materials due to their robust magnetic ordering and anisotropy.

Contribution

The paper provides detailed magnetic structure analysis of (Mo$_{2/3}$RE$_{1/3}$)$_2$AlC compounds, highlighting Gd-based materials as potential 2D magnets with high magnetic moments and stable ordering.

Findings

Gd variant exhibits a magnetic moment of 6.5 μB.

Gd compound has a Neel temperature of 29 K.

Magnetic anisotropy is extremely small, favoring in-plane interactions.

Abstract

We report muon spin rotation ($\mu$SR) and neutron diffraction on the rare-earth based magnets (Mo$_{2/3}$RE$_{1/3}$)$_2$AlC, also predicted as parent materials for 2D derivatives, where RE = Nd, Gd (only ($\mu$SR), Tb, Dy, Ho and Er. By crossing information between the two techniques, we determine the magnetic moment ($m$), structure, and dynamic properties of all compounds. We find that only for RE = Nd and Gd the moments are frozen on a microsecond time scale. Out of these two, the most promising compound for a potential 2D high ($m$) magnet is the Gd variant, since the parent crystals are pristine with $m = 6.5 \pm 0.5 \mu_B$, N\'eel temperature of $29 \pm 1$ K, and the magnetic anisotropy between in and out of plane coupling is smaller than $10^{-8}$. This result suggests that magnetic ordering in the Gd variant is dominated by in-plane magnetic interactions and should therefore remain stable if exfoliated into 2D sheets.