(07A947) Behavior of magnetic entropy change in perovskite Ba_(2-x)La_xFeMoO_6

摘要

The magneto-caloric effect and magnetization behavior have been analyzed in the double-perovskite Ba_(2-x)La_xFeMoO_6 compound with the sintering temperature and external magnetic field. Samples were fabricated by the conventional solid-state reaction method. X-ray diffraction measurements revealed that all the samples had a single phase with a cubic structure. The maximum magnetic entropy changes were obtained in the temperature range of 320-330 K for all compounds. The ΔS_M is about 0.38 J/kg K for the Ba_(2-x)La_xFeMoO_6 (x = 0.2) compound with an extemal field of 7 kOe, however, ΔS_M is about 2.93 J/kg K with a field of 15 kOe. The value of ΔS_M is increased about eight times with increasing of the external field. The enhancement of the larger magnetic entropy seems to favor the increase of magnetic order, which changes the magnetic part of the entropy of a solid around the magnetic ordering temperature.