Phase stability study of Bi0.15Sr0.85-xAexCoO3-δ (x = 0 and Ae = Ba0.28; Ca0.17) perovskites by in-situ neutron diffraction
Journal article, 2010

The oxygen deficient perovskites, Bi0.15Sr0.85-xAexCoO3-δ, x = 0 and Aex = Ba0.28, Ca0.17, were studied with in-situ neutron powder diffraction and combined TGA/DSC in order to investigate their behaviour at elevated temperatures in oxidising conditions. The phase stability of the I4/mmm supercell structure adopted by Bi0.15Sr0.85CoO3-δ is shown to be dependent on temperature and the oxygen content of the phase, with three structural events, at T 250, 590 and 880 °C, detected. The first transition occurs as the perovskite supercell vanishes due to oxygen absorption; the second transition is also associated with oxidation and involves the decomposition of the perovskite phase via an exothermic process to yield a dominant hexagonal phase. Finally, at T 900 °C the perovskite phase re-forms. For the Ba and Ca containing materials the decomposition to the hexagonal phase occurs at T 600 °C and 650 °C respectively. The presence of Ca at the A-site is found to stabilise the I4/mmm supercell structure in the range RT - 650 °C. The antiferromagnetic to paramagnetic transitions occur at TN 250 °C, TN 175 °C and TN 145 °C for the samples with Aex = Ba0.28, x = 0 and Aex = Ca0.17, respectively.

Neutron scattering

Oxides

Phase transitions

TGA

Ionic conductor

Author

Annika Eriksson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Sten Eriksson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Laurent Chapon

ISIS Facility

Christopher Knee

University of Gothenburg

Materials Research Bulletin

0025-5408 (ISSN)

Vol. 45 12 1875-1882

Subject Categories

Chemical Sciences

DOI

10.1016/j.materresbull.2010.09.004

More information

Created

10/8/2017