Magnetic entropy change in La(Fe_0.98Co_0.02)_11.7Al_1.3

Magnetization of compound La(Fe_0.98Co_0.02)_11.7Al_1.3 was measured carefully as functions of temperature and applied field around its Curie temperature of ~198 K. Magnetic entropy change |ΔS|, allowing estimation of the magnetocaloric effect (MCE), was determined based on thermodynamic Maxwell's relation. The achieved magnitude of |ΔS| reaches 10.6 J kg^-1 K^-1 under a field of 5 T. The considerable entropy change is believed to be due to the high magnetization and the sharp change in magnetization at T_C. It is found that the magnetic phase transition is completely reversible in temperature, indicating a nature of second-order phase transition.