Large magnetocaloric effect and critical behaviour analysis in Gd₂Cu₂In

¹ Highly Correlated Matter Research Group, Department of Physics, University of Johannesburg P. O. Box 524, Auckland Park 2006, South Africa
² Department of Condensed Matter Physics and Material Sciences, Tata Institute of Fundamental Research Colaba, Mumbai-400 005, India
³ Department of Physics, University of Texas at El Paso - 500 W University Ave, El Paso, TX 79968, USA
⁴ Max Planck Institute for Chemical Physics of Solids (MPICPfS) - Nöthnitzer Straße 40, 01187 Dresden, Germany

Received: 5 February 2018
Accepted: 9 May 2018

Abstract

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 .