Theoretical Work in Magnetocaloric Effect of LaFe_(13-x)Si_x Compounds

摘要

In this paper, the magnetocaloric effect (MCE) of LaFe_(13-x)Si_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 (-ΔS_M~(max)) of LaFe_(10.8)Si_(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-x)Si_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-x)Si_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_(11.8)Si_(1.2) and LaFe_(11.4)Si_(1.6) compounds in different applied magnetic fields were calculated.