Magnetocaloric Effect in DyFe3 and GdFe3

Abstract

In this work, we report on the calculation of the temperature dependence of Magnetic moment, total heat capacity and magnetocaloric effect (MCE) of DyFe3 and GdFe3 compounds. The calculation, using the Mean-Field Theory (MFT) of magnetization showed that both DyFe3 and GdFe3 are ferrimagnetic compounds with compensation temperatures around 509 K and 597 K, and Curie temperatures about 624K and 745K for DyFe3 and GdFe3 respectively. The maximum calculated 𝑖𝑠𝑜𝑡ℎ𝑒𝑟𝑚𝑎𝑙 𝑒𝑛𝑡𝑟𝑜𝑝𝑦 𝑐ℎ𝑎𝑛𝑔𝑒 |𝛥𝑆 𝑚 (𝑇, 𝛥𝐻)| are 0.21 and 0.19 J/mol.K and the maximum calculated 𝑎𝑑𝑖𝑎𝑏𝑎𝑡𝑖𝑐 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 |𝛥𝑇 𝑎𝑑 (𝑇, 𝛥𝐻)| are 0.92 and 0.82 K at 𝑓𝑖𝑒𝑙𝑑 𝑐ℎ𝑎𝑛𝑔𝑒 = 4 𝑇 for DyFe3 and GdFe3 respectively. The relative cooling powers RCP(S) and RCP(T), for a field change of 4T, are 4 and 3.8 J/mol and 19.5 and 24.6 K 2 for DyFe3 and GdFe3. Furthermore, the calculation of the critical exponents supports the suitability of the MFT for handling the systems under study. The type of the magnetic phase transition, at the Curie temperatures, is confirmed from the temperature dependence of the magnetization, heat capacity at different fields and MCE quantities to be a second order one.