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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 Na Zn13 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(-ΔSmaxM) 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(-ΔSmaxM) 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.
The structure of La1-xBixFe11.4Si1.6 compounds was investigated by X-ray diffraction and magnetization measurements. The crystal structure, magnetic properties and magnetocaloric effects (MCE) of La1-xBixFe11.4Si1.6 First, the magnetization behavior and the magnetic transition were analyzed in terms of Landau theory. Then, the Bi substitution for La in La1-xBixFe11.4Si1.6 compounds led to a decrease in magnetic entropy change (-ΔSmaxM) 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. calculated in terms of isothermal magnetic entropy change. The maximum values of (-ΔSmaxM) of La1-xBixFe11.4Si1.6 for x = 0.0 and 0.1 for these compounds were found, 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.