Effects of stacking faults on refinement of single crystal x-ray diffraction data for Sr{sub 5}Ir{sub 3}O{sub 11}

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Materials Research Bulletin

DOI:https://doi.org/10.1016/0025-5408(94)00120-0· OSTI ID:27967

Harlow, R L; Li, Z G; Marshall, W J; Crawford, M K; Subramanian, M A ^[1]

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1. Dupont Co., Wilmington, DE (United States). Central Research and Development

Single crystals with the composition Sr{sub 5}Ir{sub 3}O{sub 11} were found to grow in the system SrO-IrO{sub 2}. A single-crystal structure determination [tetragonal, space group I4/mmm, with a = 3.890(1) and c = 16.890(10) {angstrom}, and R = 0.050] revealed alternate stacking of single and double IrO{sub 6} perovskite layers interleaved with SrO layers along the c-axis. Although the refined metal-oxygen distances were quite reasonable, the thermal parameters of one heavy atom (iridium) and one light atom (oxygen) were non-positive definite. Careful examination of Weissenberg and transmission electron microscopy photographs showed that the single crystals actually contained random distributions of single and double IrO{sub 6} perovskite layers arising from the intergrowth of Sr{sub 2}IrO{sub 4} and Sr{sub 3}Ir{sub 2}O{sub 7} phases. This paper serves as a cautionary tale for those who rely solely on diffractometer data for their structural analyses.

• OSTI ID: 27967
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 2 Vol. 30; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DEFECTS
IRIDIUM OXIDES
STRONTIUM OXIDES
SUPERCONDUCTIVITY