Correlation between magnetism and magnetocaloric effects in La0.8Gd0.2Fe11.4Si1.6

In this paper, we report the correlation between magnetism and magnetocaloric effect (MCE) of La0.8Gd0.2Fe11.4Si1.6 compound. The temperature variation of magnetization in field-cool cooling (FCC) and field-cool heating (FCH) modes in fields of 500Oe, 10kOe, 30kOe and 50kOe around Tc does not show any thermal hysteresis, implying the second order nature of the magnetic transition. This observation is also supported by the thermodynamic analysis using the Landau theory of magnetic phase transitions. The MCE has been measured in terms of the isothermal magnetic entropy change (ΔSM) using the magnetization isotherms obtained at temperatures close to the ordering temperature. The maximum value of ΔSM is found to be 7.5 J/kg K for a field change of 50kOe. A comparative study of the magnetic and magnetocaloric properties of this compound with that of LaFe11.4Si1.6 will be presented in detail. (author)