Theoretical Work in Magnetocaloric Effect of LaFe_13−xSi _x Compounds

Abstract

In this paper, the magnetocaloric effect (MCE) of LaFe_13−xSi _x compounds with 1.2 ≤ x ≤ 2.2 has been investigated. For this purpose, the magnetization dependence on the temperature and magnetic field were measured. Magnetic entropy change (−ΔS_M) allowing estimation of the MCE was determined based on thermodynamic Maxwell’s relation. The experimental results show that T_C increases with the Si content, whereas the magnetic entropy variation decreases. A large magnetic entropy change has been observed. The maximum $(-\Delta \mathrm {S}_{\mathrm {M}}^{\text {max}})$ of LaFe_10.8Si_2.2 occurring close to T_C = 240 K is about 2.3 Jkg⁻¹ K⁻¹ for an applied field change of 0–2 T. In addition, a magnetocaloric effect of LaFe_13−xSi _x compounds (x = 1.2 and 1.6) has been also carried out using phenomenological model. Dependence of the magnetization on temperature variation for LaFe_13−xSi _x compounds (x = 1.2 and 1.6) in different applied magnetic fields was simulated. The values of maximum entropy change, full width at half maximum, and relative cooling power (RCP) for the LaFe_11.8Si_1.2 and LaFe_11.4Si_1.6 compounds in different applied magnetic fields were calculated.