Large magnetocaloric effect in manganese perovskite La Bi BaMnO near room temperature.

La Bi BaMnO ( = 0 and 0.05) ceramics were prepared the sol-gel method. Structural, magnetic and magnetocaloric effects have been systematically studied. X-ray diffraction shows that all the compounds crystallize in the rhombohedral structure with the 3̄ space group. By analyzing the field and temperature dependence of magnetization, it is observed that both samples undergo a second order magnetic phase transition near . The value of decreases from 340 K to 306 K when increasing from 0.00 to 0.05, respectively. The reported magnetic entropy change for both samples was considerably remarkable and equal to 5.8 J kg K for = 0.00 and 7.3 J kg K for = 0.05, respectively, for = 5 T, confirming that these materials are promising candidates for magnetic refrigeration applications. The mean-field theory was used to study the magnetocaloric effect within the thermodynamics of the model. Satisfactory agreement between experimental data and the mean-field theory has been found.