Inverse magnetocaloric effect in the solids undergoing ferromagnetic – antiferromagnetic phase transition: Landau theory applied to Fe-Rh alloys

Abstract In the present article a magnetic solid exhibiting the phase transition from the high-temperature ferromagnetic (FM) to the low-temperature antiferromagnetic (AFM) phase is considered. The Landau theory of phase transitions is used for the analysis of inverse magnetocaloric effect (MCE) observed below the phase transition temperature. The magnetic-field-induced shift of the phase transition temperature has been calculated and the dependence of the phase transition field on the temperature of solid has been computed; the quantitative agreement between the theoretical results and the experimental data obtained in the recent experiments with Fe49Rh51 alloy has been achieved. The magnetic-field-induced entropy change and refrigerant capacity of Fe49Rh51 alloy have been calculated. Reasonable agreement between theoretical results and experimental data has been demonstrated. The dependence of characteristics of MCE on the spin-exchange parameter has been shown. The MCE in the artificial AFM structures has been discussed.