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, \(- \Delta S_{M}\) vs. M² 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. M²), 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.

中文翻译：

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使用朗道理论估计 Gd3Ni2 和 Gd3CoNi 系统中的自发磁化和磁熵变

在这项工作中，我们使用平均场理论 (MFT)根据磁熵变化对磁化强度的依赖性\(- \Delta S_{M}\) vs. M ²来估计自发磁化强度M _{s pont} ( T )在 Gd ₃ Ni ₂和 Gd ₃ CoNi 系统中。获得的M _{s pont} ( T ) 值与从 Arrott 图（H / M vs. M ²)，确认 MFT 是估计自发磁化强度的有效方法。在由朗道理论估计的\(- \Delta S_{M}\)值与使用经典麦克斯韦关系获得的值之间发现了极好的一致性。