Tetragonal to monoclinic phase transformation at room temperature in Ba{sub x}Fe{sub 2x}Ti{sub 8-2x}O{sub 16} hollandite due to increased Ba occupancy

Journal Article · Tue Jun 08 04:00:00 EDT 2004 · Materials Research Bulletin

DOI:https://doi.org/10.1016/S0025-5408(04)00061-3· OSTI ID:20888079

Carter, M L

A series of barium-rich hollandite samples, of nominal stoichiometry Ba{sub x}Fe{sub 2x}Ti{sub 8-2x}O{sub 16}, with x=0.8-1.5 have been studied using scanning electron microscopy and synchrotron powder diffraction in order to establish the influence of Ba content on the phases formed. Samples with x between 1.1 and 1.3 were found to be single phase, samples with x<1.1 contained rutile as a secondary phase, and samples with x>1.3 contained (Ba, Fe) titanates as secondary phases. From synchrotron X-ray diffraction patterns, at room temperature, a transformation from the tetragonal (I4/m) to the monoclinic (I2/m) structure was observed between x=1.1 and 1.2. The monoclinic angle, {beta} increases rapidly from 90.48(2) to 91.06(6) deg. as x increased from 1.2 to 1.4.

• OSTI ID: 20888079
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 7-8 Vol. 39; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM
CERAMICS
HOLLANDITE
MONOCLINIC LATTICES
PHASE TRANSFORMATIONS
RUTILE
SCANNING ELECTRON MICROSCOPY
STOICHIOMETRY
SYNCHROTRONS
TEMPERATURE RANGE 0273-0400 K
TETRAGONAL LATTICES
TITANATES
X-RAY DIFFRACTION