The symmetry aspect of magnetocaloric effect in LaxBi0.3-xCa0.7MnO3 manganites.

Manganites exhibit many novel properties, such as giant magnetoresistance and a large magnetocaloric effect (MCE). In this work, we report the magnetic properties and magnetocaloric effects of polycrystalline Bi 0.3- x La x Ca 0.7 MnO 3 (x = 0, 0.1, 0.2) ceramics from perspective of symmetry, where Raman active modes and corresponding phonons are used as probes to detect charge disorder and local structure distortion. Further, the large MCE is elucidated by the La doping induced Jahn-Teller distortion and valence perturbations. The orthorhombic and rhombohedral structural transition in doping manganites has shown a link between the complex magnetic phase transition and magnetic entropy. We attribute these intriguing behaviors to the temperature-dependent competition between the orbital order and charge order. Our results provide an approach to improve the MCE of manganite systems for future magnetic refrigeration applications. [ABSTRACT FROM AUTHOR]