Layered crystal structure oxide
US6143679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1997 |
| Grant date | Nov 7, 2000 |
| Priority date | — |
| Expiry date | Oct 3, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B29/32
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Provided are a layered crystal structure oxide showing ferroelectricity or paraelectricity and a process for easily producing the same. A raw material containing Bi.sub.2 O.sub.3 as a flux is heated up to 1330.degree. C. or higher and 1450.degree. C. or lower at a suitable temperature-elevating rate (heating step); the raw material is maintained at this heating temperature for prescribed time (constant temperature step); and then, it is slowly cooled down to 800.degree. C. or higher and 1300.degree. C. or lower at a rate of 1.degree. C./hour or more and 20.degree. C./hour or less (slow cooling step). This makes it possible to evaporate the flux and take out directly Bi.sub.2 SrTa.sub.2 O.sub.9. In this Bi.sub.2 SrTa.sub.2 O.sub.9, Bi is partially substituted with Sr, and oxygen is selectively deficient or disordered. Or, Bi and O in the fluorite layer are relatively displaced each other in the polarization direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.