Abstract
In this work, we used the mean-field theory (MFT) to estimate the spontaneous magnetization M-spont(T) from the dependence of magnetic entropy change on magnetization, -Delta(SM) vs. M-2 in Gd3Ni2 and Gd3CoNi systems. The obtained M-spont(T) values are in good agreement with those found from the classical extrapolation from the Arrott plots (H/M vs. M-2), confirming that the MFT is a valid approach to estimate the spontaneous magnetization. An excellent agreement has been found between the -Delta S-M values estimated by Landau theory and those obtained using the classical Maxwell relation.