Abstract
We present a theoretical study, based on the mean-field theory, on magnetocaloric effect in both amorphous GdxCo1-x (0.16 <= x <= 0.25) and GdxFe1-x (x = 0.263 and 0.306) alloys in a temperature range up to Curie temperature and in magnetic fields up to 70 kOe. Our calculations show a fair agreement with available experimental data which confirm ferrimagnetic order in these systems. Both direct and inverse magnetocaloric effects are present. For Gd0.16Co0.84, maxima of delta S-m are 1.32 and 1.62 J/kg K for magnetic field changes of 40 and 70 kOe respectively. However, the peak values of delta S-m decrease as x increases. Peak values of delta S-m are 0.64 and 0.82 J/K.kg for Gd(0.263)Fe(0.737 )and Gd0.306Fe0.694 respectively. The Belov-Arrott plots, the universal curve, and temperature dependence of delta S-m for Gd-Co alloys, showed that the alloys exhibit a second order phase transition at their Curie temperatures. The same conclusion is reached for Gd-Fe alloys.
NSTL
Elsevier