Landau mean-field analysis and estimation of the spontaneous magnetization from magnetic entropy change

[Display omitted] •The La1-x□xMnO3 (x = 0.1, 0.2 and 0.3) compounds was successfully prepared by sol–gel method.•The variation of (M) vs. (T) reveals a ferromagnetic to paramagnetic phase transition around TC.•we investigated the critical exponents for the compounds La1-x□xMnO3 (x = 0.1; 0.2 and 0.3) We investigated the critical exponents for the compounds La1-x□xMnO3 (x = 0.1; 0.2 and 0.3) prepared bythe sol–gel method. Our samples show a second-ordertransition inferred from the positive slope, in accordance with the Banerjee Criterion. Using the slope of different models on the TC, the relative slope (RS) was traced. From this perspective, the best models for the three samples prove to be the mean field and thetricriticalmean field models. This model is characterized by critical exponents β, γ and δ which are determinedby many methods such as MAP, KF method and critical isotherm analysis. The theoritical methods and experimental results were in good agreement for the three compounds. The universality class has been shown. After determining the spontaneous magnetization for x = 0.2 from (-ΔSM) vs. M2, we detected a good agreement with those obtained from the classical extrapolation of Arrott curves (µ0H/M vs. M2). Furthermore, based on the magnetocaloric effect (MCE), Landau’s theory is valid for the compound x = 0.2.