Magnetic and magnetocaloric properties of Gd(Ni1−xFex)2 quasi-binary Laves phases with x = 0.04 ÷ 0.16

In this paper the results of specific magnetization (M), heat capacity (Cp) and magnetocaloric effect (MCE) measurements for Gd(Ni1−xFex)2 system over the Ni substitution by Fe range of x = 0 ÷ 0.16 are presented. Phase composition was controlled by X-ray diffraction analysis. Heat capacity was measured in the temperature range 77 ÷ 320 K. MCE has been studied within the temperature range 5 ÷ 400 K in magnetic fields up to 70 kOe by the entropy magnetic contribution change calculation (ΔSm) and by direct ΔTad measurements at the adiabatic conditions for external magnetic field change ΔH = ±17.5 kOe. It was found that the Fe concentration increase causes both the Cp maxima disappearing at Curie temperature point and emergence of magnetic contribution to Cp in a wide temperature range below this point. Moreover, in compounds with iron, a plateau-like temperature dependence of the MCE was observed for both magnetic entropy change (ΔSm) and direct ΔTad data which are independent on Fe concentration. The possible reasons of such behavior are discussed.