Aging dynamics of ferromagnetic and reentrant spin glass phases in stage-2 Cu$_{0.80}$C$_{0.20}$Cl$_{2}$ graphite intercalation compound

TL;DR

This study investigates the aging dynamics of a reentrant ferromagnet graphite intercalation compound, revealing complex relaxation behavior and memory effects in both ferromagnetic and spin glass phases through magnetic susceptibility measurements.

Contribution

It provides new insights into aging phenomena and memory effects across phase transitions in a reentrant ferromagnetic compound, highlighting the frustrated magnetic nature.

Findings

Peak in relaxation rate at characteristic time varies with temperature.

Memory of aging is retrievable as anomalies in thermoremnant magnetization.

Aging phenomena occur in both ferromagnetic and spin glass phases.

Abstract

Aging dynamics of a reentrant ferromagnet stage-2 Cu$_{0.8}$Co$_{0.2}$Cl$_{2}$ graphite intercalation compound has been studied using DC magnetic susceptibility. This compound undergoes successive transitions at the transition temperatures $T_{c}$ ($\approx 8.7$ K) and $T_{RSG}$ ($\approx 3.3$ K). The relaxation rate $S_{ZFC}(t)$ exhibits a characteristic peak at $t_{cr}$ below $T_{c}$. The peak time $t_{cr}$ as a function of temperature $T$ shows a local maximum around 5.5 K, reflecting a frustrated nature of the ferromagnetic phase. It drastically increases with decreasing temperature below $T_{RSG}$. The spin configuration imprinted at the stop and wait process at a stop temperature $T_{s}$ ($<T_{c}$) during the field-cooled aging protocol, becomes frozen on further cooling. On reheating, the memory of the aging at $T_{s}$ is retrieved as an anomaly of the thermoremnant magnetization at $T_{s}$. These results indicate the occurrence of the aging phenomena in the ferromagnetic phase ($T_{RSG}<T<T_{c}$) as well as in the reentrant spin glass phase ($T<T_{RSG}$).