Large magnetocaloric effect and critical behaviour analysis in Gd2Cu2In

The ternary intermetallic compound Gd2Cu2In crystallizes in the Mo2Fe2B-type structure with the space group P4/mbm. The compound undergoes a ferromagnetic-paramagnetic (FM-PM) phase transition at 94.1K and large magnetocaloric effect has been observed over a wide range of temperature. The isothermal magnetic entropy change (Delta Sm) and adiabatic temperature change (Delta T-ad) were observed to be 13.8 J/kg.K and 6.5K for 7T 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 beta = 0.312(2) and gamma = 1.080(5) are estimated through a non-linear fitting. The beta value is close to the three-dimensional (3D) Ising value, whereas gamma and delta values lie closer to the mean-field values. Scaled magnetic isotherms collapse into two branches below and above TC in accordance with a single scaling equation. Specific-heat measurements show a lambda-type peak near 94K indicating long-range magnetic ordering. The specific-heat exponent a was estimated by a non-linear fitting using the function C-P = B + Cc + A(+/-)|c|(-alpha) (1 + E-+/-|c|(0.5)). The fitting in the temperature range -0.025 < c < 0.025 yields alpha = 0.11(3). Copyright (C) EPLA, 2018.