Large magnetocaloric effect and critical behaviour analysis in Gd₂Cu₂In

The ternary intermetallic compound Gd₂Cu₂In crystallizes in the Mo₂Fe₂B-type structure with the space group . The compound undergoes a ferromagnetic-paramagnetic (FM-PM) phase transition at 94.1 K and large magnetocaloric effect has been observed over a wide range of temperature. The isothermal magnetic entropy change and adiabatic temperature change were observed to be 13.8 J/kg • K and 6.5 K for 7 T applied field. We have employed a modified Arrott plot (MAP) and Kouvel-Fisher (KF) procedures to estimate the critical exponents near the FM-PM phase transition. Critical exponents and are estimated through a non-linear fitting. The β value is close to the three-dimensional (3D) Ising value, whereas γ and δ values lie closer to the mean-field values. Scaled magnetic isotherms collapse into two branches below and above T _C in accordance with a single scaling equation. Specific-heat measurements show a λ-type peak near 94 K indicating long-range magnetic ordering. The specific-heat exponent α was estimated by a non-linear fitting using the function . The fitting in the temperature range yields .