Magnetocaloric properties of (La0.67-xGdx)Sr0.33MnO3 polycrystalline nanoparticles

In this paper, magnetic property and magnetocaloric effect (MCE) in nanoparticles perovskite manganites of the type (La0.67-xGdx)Sr0.33MnO3 (x = 0.10, 0.15, 0.20) synthesized by using an amorphous molecular alloy as precursor have been reported. From the magnetic measurements as function of temperature and magnetic applied field, we have discovered that the Curie temperature (TC) of the prepared samples is found to be strongly dependent on Gd content. The Curie temperature of samples is 358.4, 343.2, and 285.9 K for x = 0.1, 0.15, and 0.2, respectively. A large magnetocaloric effect close to T-C has been observed with a maximum of magnetoentropy change in all the samples, |Delta S-M|(max) of 1.96 and 4.90 J/kg K at 2 and 5T, respectively, for a substitution rate of 0.15. In addition, the maximum magnetic entropy change observed for samples with different concentration of Gd, exhibits a linear dependence with the applied high magnetic field. These results suggest that (La0.67-x Gd-x)Sr0.33MnO3 (x = 0.10, 0.15, 0.20) compounds could be a suitable candidate as working substance in magnetic refrigeration near room temperature. (C) 2009 Published by Elsevier B. V.