X-ray photoelectron study on Ba_(0.5)Sr_(0.5)Co_xFe _(1-x)O_(3-δ) (BSCF: _X 0.2 and 0.8) ceramics annealed at different temperature and _pO_2

摘要

X-ray diffraction (XRD) and the X-ray photoelectron spectroscopy (XPS) were measured for the sintered BSCF ceramics (Ba_(0.5)Sr _(0.5)Co_xFe_(1-x)O_(3-δ) x = 0.2 and 0.8: BSCF5528 and BSCF5582, respectively), which were annealed at different temperatures (700 and 950 °C) and gases (O_2 and Ar). The unit cell of the annealed BSCF5528 at 950 °C under Ar expanded by 0.8%, while contracting by 0.45% under O_2. The cubic and rhombohedral phases coexist in the BSCF5582 annealed at 700 °C under O2. The XPS peak areas of lattice oxygen (O~(2-) in O_(1s), ? 528 eV, and the shoulder peak of Co_(2p)/Ba_(3d) in BSCF5582 (? 778 eV) increased significantly after being annealed in O_2. The areas of the peaks for BaCO_3 (87.9/ 90.2 eV) in Ba4d preferentially were shown to decrease in Ar and increase in O_2.