Magnetocaloric Effect in DyFe 3 and GdFe 3

Abstract

Magnetic compounds have attracted attention during several years, especially rare earth intermetallic compounds, for their fundamental physics of magnetism and technological impact e.g. magnetic refrigeration. The calculations of temperature dependence of magnetization, magnetic heat capacity and magnetocaloric effect (MCE) properties have been performed on DyFe3 and GdFe3 compounds. The magnetization dependence on temperature by using mean field theory (MFT), showed that both DyFe3 and GdFe3 are ferrimagnetic compounds. Direct and inverse MCE are present in these compounds. The maximum observed isothermal entropy change are 0.2 and 0.19 J/ mole K at ΔH = 4 T using Maxwell relation and the maximum values of adiabatic change in temperature are 0.95 and 0.8 K at ΔH=4 T for DyFe3 and GdFe3 respectively. The relative cooling power RCP(S) for DyFe3 and GdFe3 are 3.4 and 3.8 J/mol for a field change ΔH = 4T respectively. The relative cooling power is based on the adiabatic temperature change, RCP(T) are 14.7 and 22.4 K2 at ΔH = 4T. The calculations of the critical exponents add more evidence of the suitability of the mean-field theory to handle the systems under study.