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Observation of Magnetic Phase Transition and Magnetocaloric Effect in Ba{sub 1−x}Sr{sub x}MnO{sub 3−δ}

Journal Article · · Journal of Superconductivity and Novel Magnetism
; ;  [1]
  1. Shanghai University, Department of Physics, Materials Genome Institute (China)
A series of perovskite materials (BaMnO{sub 3−δ} and Ba{sub 1−x}Sr{sub x}MnO{sub 3}) were synthesized by a solid-state reaction method. The content of oxygen vacancy can be controlled by verifying the sintering temperature and atmosphere. Two obvious divarications between zero-field-cooling curves and field-cooling curves were observed in a high-temperature region of 250–300 K and at a low temperature of 40 K, respectively. It is found that the different oxygen vacancy contents in BaMnO{sub 3−δ} cause the change of crystalline structure and variation of the divarication temperature at a high-temperature region. The factor that controls the negative magnetic susceptibility was discussed. The superexchange interaction between Mn ions can give rise to the coexistence of the ferromagnetic phase and antiferromagnetic phase in the system. We further performed the study of magnetocaloric effect in Sr-doped BaMnO{sub 3}. However, the values of magnetic entropy change and refrigeration coefficient are much smaller than those of rare-earth manganites due to the weak magnetocrystalline anisotropy in Ba{sub 1−x}Sr{sub x}MnO{sub 3}.
OSTI ID:
22773636
Journal Information:
Journal of Superconductivity and Novel Magnetism, Journal Name: Journal of Superconductivity and Novel Magnetism Journal Issue: 11 Vol. 31; ISSN 1557-1939
Country of Publication:
United States
Language:
English