Spin–glass behavior in Shastry–Sutherland lattice of Tm₂Cu₂In

The spin–glass behavior in the ferromagnetic phase of Tm₂Cu₂In was investigated by dc–, ac–magnetization, and non-equilibrium dynamics characterizations. An argon arc–melted polycrystalline sample of the compound of Tm₂Cu₂In was found to adopt the Mo₂FeB₂–type tetragonal structure (space group P₄/mbm). The temperature variation of 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 the thermomagnetic irreversible behavior below T_C. The field dependence of irreversible temperature follows the Almeida–Thouless line. The frequency and ac–driven field dependent anomalies in ac–susceptibility results indicate the existence of a spin–glass state in Tm₂Cu₂In. The time dependence of magnetization further supports the spin–glass behavior observed in Tm₂Cu₂In. The frequency dependence of the freezing temperature in the real part of ac–susceptibility has been analyzed on the basis of a power–law divergence and Vogel–Fulcher law. The obtained results reveal that Tm₂Cu₂In belongs to the ferromagnetic canonical spin–glass class of compounds.