Modeling the Magnetocaloric Effect of La0.67Pb0.33MnO3 by the Mean-Field Theory

In this paper, a theoretical analysis linked to the molecular field theory and the Bean-Rodbell model has investigated the magnetocaloric effect (MCE) in a La0.67Pb0.33MnO3 sample. We have demonstrated how the mean-field model can adequately simulate the magnetic and magnetocaloric properties of this magnetic system, which may be a candidate material to magnetic refrigerants. The second-order ferromagnetic (FM)-paramagnetic (PM) phase transition has been confirmed. The expressions describing the entropy and its change under the influence of the magnetic field have been derived. A scaling method based on the mean-field theory leads to a direct calculation of the exchange parameter (λ), the saturation magnetization (M0), the total angular momentum (J), and the gyromagnetic factor (g) of our sample. These constants were used to simulate M(H,T) isotherms, which are used again for the determination of the magnetic entropy change (−ΔSM) of La0.67Pb0.33MnO3.