Near room temperature magneto caloric effect in V doped La0.67Ca0.33MnO3 ceramics

La0.67Ca0.33MnO3 doped with different amounts of V, resulting in the series La0.67Ca0.33Mn1-xVxO3 [x = 0.03, 0.06, 0.1, 0.15, 0.25, 0.5] was synthesized by conventional solid-state ceramics route. Heat treatment conditions during synthesis were optimized to have small changes in the Curie temperature (T-C). The compounds with x > 0.06 were found to have the additional LaVO4 phase. A quantitative analysis of the extra phase with increase in V doping was investigated by the Rietveld refinement of the X-ray diffraction patterns. Variation of magnetic and magnetocaloric properties at different temperatures and magnetic fields was studied. Magnetocaloric effect has been studied in terms of isothermal magnetic entropy change (Delta S-M). Magnetization was found to change drastically at around 275 K and the isothermal magnetic entropy change was found to peak in the temperature range 265-275 K. With increase in V content, Delta S-M initially shows a considerable increase and then a decrease at higher V concentrations. (C) 2008 Elsevier B.V. All rights reserved.