Ferromagnetic cluster spin-glass behavior in PrRhSn3

Abstract: We report the synthesis, structure, and magnetic and transport properties of a new ternary intermetallic compound PrRhSn3 which crystallizes in LaRuSn3-type cubic structure (space group Pm-3n). At low applied fields the dc magnetic susceptibility exhibits a sharp anomaly below 6~K with an irreversible behavior in zero field cooled (ZFC) and field cooled (FC) susceptibility below 5.5 K. The ac susceptibility exhibits a frequency dependent anomaly revealing a spin-glass behavior with a freezing temperature, T_f = 4.3 K. The observation of spin-glass behavior is further supported by a very slow decay of thermo-remnant magnetization (mean relaxation time tau = 2149 s). However, a small jump at very low field in the isothermal magnetization at 2 K and a weak anomaly in the specific heat near 5.5 K reveal the presence of ferromagnetic clusters. The frequency dependence of the transition temperature T_f in the ac susceptibility obeys the Vogel-Fulcher law, nu = nu_0exp[-E_a/k_B(T_f-T_0)] with activation energy E_a/k_B = 19.1 K. This together with an intermediate value of the parameter delta T_f = Delta T_f/T_f Delta(log nu) = 0.086 provide an evidence for the formation of a cluster-glass state in PrRhSn3. The magnetic contribution of the specific heat reveals a broad Schottky-type anomaly centered around 10 K and the analysis based on the crystal electric field model indicates a singlet ground state. Further, below T_f the magnetic part of the specific heat exhibits a T^{3/2} temperature dependence. The strong influence of the crystal electric field and a T^{3/2} temperature dependence are also seen in the electrical resistivity which reveals a metallic character and a high magnetoresistance. We also obtain a surprisingly large value of Sommerfeld-Wilson ratio R_W ~ 247$.