Magnetocaloric and transport study of poly- and nanocrystalline composite manganites La0.7Ca0.3MnO3/La0.8Sr0.2MnO3

Magnetocaloric and transport properties are reported for novel poly-and nanocrystalline double composite manganites, La0.8Sr0.2MnO3/La0.7Ca0.3MnO3, prepared by the sol-gel method. Magnetic field dependence of magnetic entropy change is found to be stronger for the nano-than the polycrystalline composite. The remarkable broadening of the temperature interval, where the magnetocaloric effect occurs in poly-and nanocrystalline composites, causes the relative cooling power (RCP(S)) of the nanocrystalline composite to be reduced by only 10% compared to the Sr based polycrystalline phase. The RCP(S) of the polycrystalline composite becomes remarkably enhanced. The low temperature magnetoresistance is enhanced by 5% for the nanostructured composite. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739262]