Effect of Ti-substitution on magnetic and magnetocaloric properties of La0.57Nd0.1Pb0.33MnO3

We have studied the effect of Ti substitution on magnetic and magnetocaloric properties in La0.57Nd0.1Pb0.33Mn1-xTixO3 (x = 0.1 and x = 0.15) over a wide temperature range (T = 240-340 K). The prepared samples remain single phase and exhibit paramagnetic (PM)-ferromagnetic (FM) phase transition (T-C) at 300 and 280K for x = 0.1 and x = 0.15, respectively. From the magnetic measurements as function of temperature and magnetic applied field, we have discovered a large magnetic entropy change (-Delta S-M) at Curie temperature. Delta S-M has been deduced by two methods: Maxwell relation and Landau theory. The maximum value of the magnetic entropy change obtained from the M(H) curves and it increases with increase of Ti content from 4.85 J kg(-1) K-1 at 299K to 5.2 J kg(-1) K-1 at 279 K, under Delta H = 5T. The field dependence of the magnetic entropy change is also analyzed showing the power law dependence, Delta S-M proportional to H-n where n = 0.610(3) for x = 0.1 and n = 0.525(5) for x = 0.15 at their respective transition temperatures. The relative cooling power (RCP) and its field dependence are also analyzed. The obtained results show that La0.57Nd0.1Pb0.33Mn1-xTixO3 could be considered as a potential candidate for magnetic refrigeration applications around room temperature. (C) 2012 Published by Elsevier B.V.