Influence of bismuth on magnetism and magnetocaloric properties of LaFe11.6Si1.4 intermetallic compound

Crystal structure, magnetic properties and magnetocaloric effects (MCE) of La1–xBixFe11.4Si1.6 (x=0.0 and 0.1) compounds were investigated by X-ray diffraction and magnetization measurements. The La1–xBixFe11.4Si1.6 compounds presented a cubic NaZn13 type structure. First, the magnetization behavior and the magnetic transition were analyzed in terms of Landau theory. Then, Bi substitution for La in La1–xBixFe11.4Si1.6 compounds led to a decrease in magnetic entropy change () but an increase in Curie temperature (TC) significantly. The significant increase of TC by Bi substitution from 202.5 to 256 K for x=0.0 and x=0.1 respectively was attributed to an increase in the Fe-Fe exchange interactions. Moreover, magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. The maximum values of () of La1–xBixFe11.4Si1.6 for x=0.0 and 0.1 compounds were found to be, respectively, 22.56 and 4.36 J/(kg·K) under an applied magnetic field change of 5 T. For the same applied magnetic field (μ0H=5 T), the relative cooling power (RCP) values were found to vary between 487 and 296 J/kg.

Temperature dependence of the magnetic entropy change under a magnetic field change from 0 to 5T for La1–xBxFe11.4Si1.6 (x=0.0 and x=0.1) compoundsFigure optionsDownload as PowerPoint slide