Effect of partial substitution of Mn by Fe on the structure, magnetic phase transition and magnetocaloric response in La0.67Pb0.33Mn1-xFexO3 compounds

The compounds La0.67Pb0.33Mn1-xFexO3 (0x0.10) have been fabricated by ceramic procedures mainly to investigate their structure, magnetic phase transition and magnetocaloric effect. All samples have a rhombohedral structure belonging to R space group by structural analysis. As the Fe concentration x increases up to 0.10, Curie temperature value significantly decreases from 360 to 210K. The maximum values of MEC (magnetic entropy change) are found to be 4.17, 2.99, 2.58Jkg(-1)K(-1) under 5T field change for x=0, 0.05, 0.10, respectively. The corresponding values of RCP (relative cooling power) are 229.8, 235.4, 216.5Jkg(-1). The relatively large MEC, high RCP values and the convenient adjustment of the T-C suggest that the prepared La0.67Pb0.33Mn1-xFexO3 compounds could be appropriate materials for magnetic cooling in a wide working temperature range. The analysis of isothermal magnetization using the Arrott curves and Franco's universal method reveals that the La0.67Pb0.33Mn1-xFexO3 manganites show a second-order ferromagnetic-paramagnetic transition.