Influence of Fe doped on the magnetocaloric behavior of La${}_{2/3}$Ca${}_{1/3}$Mn_1−xFe_xO₃ compounds: a Monte Carlo simulation

The magnetocaloric behavior of La${}_{2/3}$Ca${}_{1/3}$Mn_1−xFe_xO₃ for x  =  0.00, 0.02, 0.03, 0.05, 0.07, 0.08 and 0.10 under the influence of an external magnetic field was simulated and analyzed. Simulations were carried out using the Monte Carlo method and the classical Heisenberg model under the Metropolis algorithm. These mixed valence manganites are characterized by having three types of magnetic ions corresponding to $M{n}^{4+}(S=\frac{3}{2})$, which are bonded with $C{a}^{2+}$, and $M{n}_{e_g}^{3+}$ and $M{n}_{e_g^{\prime }}^{3+}$ $(S=2)$, related to $L{a}^{3+}$. The $Fe$ ions were randomly included, replacing $Mn$ ions. With this model, the magnetic entropy change, $\Delta S$, in an isothermal process was determined. $-\Delta S_m$ showed maximum peaks around the paramagnetic-ferromagnetic transition temperature, which depends on $Fe$ doping. Relative cooling power was computed for different $Fe$ concentrations varying the magnetic applied field. Our model and results show that the $Fe$ doping decreases the magnetocaloric effect in the La${}_{2/3}$Ca${}_{1/3}$Mn_1−xFe_xO₃, making this a bad candidate for magnetic refrigeration. The strong dependence of the magnetocaloric behavior on $Fe$ doping and the external magnetic field in La${}_{2/3}$Ca${}_{1/3}$Mn_1−xFe_xO₃ can boost these materials for the future technological applications. (paper)