Re-entrant spin glass behaviour and large magnetocaloric effect in Er₂PtSi₃

We present the magnetic properties and magnetocaloric effect of ternary intermetallic compound Er₂PtSi₃ with the orthorhombic Ba₂LiSi₃-type structure. Dc magnetization, ac susceptibilit, magnetic relaxation, electrical resistivity and specific heat measurements indicate that this system undergoes two magnetic phase transitions from a paramagnetic state sequentially to an antifwerromagnetic state at T_N=5.4 K and then to a random spin freezing state at T_f=2.4 K. In addition, the large magnetocaloric effect is also observed for the Er₂PtSi₃ alloy. Near its Néel temperature T_N, the maximum magnetic entropy change, relative cooling power and maximum adiabatic temperature change are estimated to be 16.1 Jkg^-1K^-1, 290 Jkg^-1 and 7.7 K, respectively, for a field change of 5 T. These results suggest that Er₂PtSi₃ should be classified as a re-entrant spin-glass system and can be considered as a potential lowerature magnetic refrigeration material.