Magnetic phase diagram and cluster glass-like properties of stage-1 graphite intercalated FeCl$_3$

TL;DR

This study explores the complex magnetic phase diagram of stage-1 FeCl3 graphite intercalation, revealing multiple magnetic transitions, cluster glass behavior, and potential topologically non-trivial phases in a frustrated van der Waals system.

Contribution

It provides the first detailed magnetic phase diagram of FeCl3 intercalated graphite, identifying two phase transitions and evidence of cluster glass-like properties and long-range order.

Findings

Two magnetic phase transitions at 4.2 K and 2.7 K.

Presence of short-range ferromagnetic correlations above 4.2 K.

Observation of cluster glass-like behavior between 4.2 K and 2.7 K.

Abstract

We present a comprehensive investigation of the magnetic properties of stage-1 graphite intercalated FeCl$_3$ using a combination of DC and AC magnetic susceptibility, thermoremanent magnetization and field dependent magnetization measurements. This van der Waals system, with a centrosymmetric honeycomb lattice, combines frustration and disorder, due to intercalation, and may be hosting topologically non-trivial magnetic phases. Our study identifies two magnetic phase transitions at $T_{f1} \approx $ 4.2 K and at $T_{f2} \approx $ 2.7 K. We find that the paramagnetic state, for $T > T_{f1}$, is dominated by short-range ferromagnetic correlations. These build up well above $T_{f1}$ and lead to a significant change in magnetic entropy, which reaches $\Delta S_M^{Pk} = $ -5.52 J kg$^{-1}$ K$^{-1}$ at 7 T. Between $T_{f1}$ and $T_{f2}$ we observe slow spin dynamics characteristic of a cluster glass-like state, whereas for $T$ $ < $ $T_{f2}$ our results indicate the onset of a low temperature long range ordered state. The analysis of the experimental results leads to a complex phase diagram, which may serve as a reference for future investigations searching for topological non-trivial phases in this system.