Comparative Study of Magnetocaloric Effect in La 0.67 Ca 0.20 Sr 0.13 MnO 3 Manganite Prepared by Sol-Gel Method and Spark Plasma Sintering

The La0.67Ca0.20Sr0.13MnO3 nanoparticles and bulks were prepared by using sol-gel method (SGM) and spark plasma sintering (SPS), respectively. The X-ray diffraction analysis indicates each sample crystal in a single rhombohedral perovskite structure (space group \(R\overline {3}c\)). The Curie temperature is slightly improved and the phase transition is sharpened after processing with SPS. The enhancement of magnetocaloric effect (MCE) is also observed in the samples prepared by SPS. For a field change of 3 T, the maximum isothermal entropy change is improved by 32 and 117% when different sintering temperatures and sintering pressures are applied. The magnetic phase transition and MCE can be well described by the Landau theory. The present studies suggest that the perovskite bulks prepared by SPS could be useful for the application of magnetic refrigeration.