Size-induced changes of structural, magnetic and magnetocaloric properties of La0.7Ca0.2Ba0.1MnO3

The particle size effects on the structural, magnetic and magnetocaloric properties of La0.7Ca0.2Ba0.1MnO3 (LCBMO) manganites have been studied systematically. It is found that the sintering temperature could affect the micro-structures and the magnetic properties of these compounds intensively. The variations in the magnetic properties as a function of the particle size may be attributed to the local lattice distortion. With increase in the particle size, the Griffiths-phase-like behavior of susceptibility around the paramagnetic region is gradually suppressed. Furthermore, the maximum magnetic entropy change -Delta S-M(max) gradually increases with increase in the particle size. For the sample with the largest particle size (7600 nm), the values of -Delta S-M(max) were approximately 5.95 and 3.82 J/kg K with the magnetic field changes Delta H=45 and 20 kOe, respectively. The relative cooling power (RCP) exhibits the non-monotonic dependence on the particle size. The maximum values of RCP could reach 239.6 and 102.9 J/kg with Delta H=45 and 20 kOe, respectively, indicating LCBMO manganites could be promising candidates for the refrigerant materials of magnetic refrigerators. (c) 2010 Elsevier B.V. All rights reserved.