Cation Disorder in the Ferroelectric Oxides ABi2Ta2O9, A=Ca, Sr, Ba

✍ Scribed by René Macquart; Brendan J. Kennedy; Yuichi Shimakawa

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 350 KB
• Volume: 160
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9216

✦ Synopsis

The crystal structures of the layered ferroelectric oxides ABi 2 Ta 2 O 9 (A ‫؍‬ Ca, Sr, and Ba) have been re5ned using multiple-wavelength synchrotron powder di4raction data. At room temperature CaBi 2 Ta 2 O 9 and SrBi 2 Ta 2 O 9 have an orthorhombic structure with space group A2 1 am. Bulk samples of the two oxides exhibit small, but signi5cant amounts of disorder between the A-type and Bi atoms. BaBi 2 Ta 2 O 9 has a tetragonal structure, space group I4/mmm. Again signi5cant amounts of cation disorder are detected.