Effect of Al substitution on magnetocaloric effect in La0.57Nd0.1Sr0.33Mn1-xAlxO3 (0.0 ≤ x ≤ 0.30) polycrystalline near room temperature

We have investigated the effect of aluminum (Al) doping on the magnetic and magnetocaloric properties of La0.57Nd0.1Sr0.33Mn1-xAlxO3 (LNSMAO) (0.0 <= x <= 0.3). The Curie temperature T-C of the prepared samples is found to be strongly dependent on the aluminum content and it spans between 238 K and 342 K. It has been analyzed by using two methods: a linear extrapolation of M (T) to zero magnetization and the thermodynamic model. With an increasing Al concentration, a systematic increase in the values of magnetic entropy is observed. The magnitude of the isothermal magnetic entropy (vertical bar Delta S-M vertical bar) at the FM Curie temperature increases from 2.31 J/kg K for x = 0 to a maximum value of 3.58 J/kg K for x = 0.3 for a magnetic field change of 10 kOe. Moreover, the relative cooling power (RCP) increases from 23 J/kg to 68 J/kg, respectively. Large magnetic entropy changes upon the application of a low magnetic field and a wide temperature range of TC suggest that these materials can be used as candidates for magnetic refrigerants. (C) 2011 Elsevier B. V. All rights reserved.