Size-induced changes of structural, magnetic and magnetocaloric properties of La 0.7Ca 0.2Ba 0.1MnO 3

The particle size effects on the structural, magnetic and magnetocaloric properties of La _0.7Ca _0.2Ba _0.1MnO ₃ (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 -∆SMmax gradually increases with increase in the particle size. For the sample with the largest particle size (7600 nm), the values of -∆SMmax were approximately 5.95 and 3.82 J/kg K with the magnetic field changes ∆ Н=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 ∆ Н=45 and 20 kOe, respectively, indicating LCBMO manganites could be promising candidates for the refrigerant materials of magnetic refrigerators.