Spin-glass behavior in Shastry-Sutherland lattice of Tm$_\textbf{2}$Cu$_\textbf{2}$In

Abstract

The spin-glass behavior in the ferromagnetic phase of $\mathrm{Tm_2Cu_2In}$ was investigated by dc-, ac-magnetization, and non-equilibrium dynamics characterizations. Arc-melted polycrystalline compound of $\mathrm{Tm_2Cu_2In}$ crystallizes in $\mathrm{Mo_2FeB_2}$-type tetragonal structure (space group $P_4/mbm$). The temperature variation dc-magnetization exhibits a ferromagnetic behavior with Curie temperature $T_C$ = 32.5 K. The zero-field cooled (ZFC) and field cooled (FC) magnetic curves show a thermomagnetic irreversible behavior below $T_C$. The field dependence of irreversible temperature follows Almeida-Thouless line. The frequency and ac-driven field-dependent anomalies in ac-susceptibility results indicate the existence of spin-glass state in $\mathrm{Tm_2Cu_2In}$. The time dependence of magnetization further supports the spin-glass behavior observed in $\mathrm{Tm_2Cu_2In}$. The frequency dependence of the freezing temperature in the real part of ac-susceptibility has been analyzed on the basis power-law divergence and Vogel-Fulcher law. The obtained results revealed that $\mathrm{Tm_2Cu_2In}$ belongs to a ferromagnetic canonical spin-glass class of compounds.