Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-25T17:40:56.114Z Has data issue: false hasContentIssue false
  • English
  • Français

Calcium Site Occupancy in BaTiO3

Published online by Cambridge University Press:  21 February 2011

H. M. Chan ,
M. P. Harmer ,
M. Lal  and
D. M. Smyth
H. M. Chan
Affiliation:
Materials Research Center, Lehigh University, Bethlehem, PA 18015, U.S.A.
M. P. Harmer
Affiliation:
Materials Research Center, Lehigh University, Bethlehem, PA 18015, U.S.A.
M. Lal
Affiliation:
Materials Research Center, Lehigh University, Bethlehem, PA 18015, U.S.A.
D. M. Smyth
Affiliation:
Materials Research Center, Lehigh University, Bethlehem, PA 18015, U.S.A.
Get access

Abstract

Measurements of the equilibrium electrical conductivity of Ca-doped BaTiO3 indicate a highly acceptor-doped behavior when y > 1 in the general formula (Ba1−xCaxO)yTiO2. It has been suggested that when there is an excess of alkaline earth oxides, some Ca++ occupies Ti-sites, where it acts as a doubly charged acceptor, CaTi''. This possibility has been checked with a recently developed technique for determining the crystallographic site occupancy of impurity atoms. Known as ALCHEMI (Atom Location Using Channeling-Enhanced Microanalysis), the technique relies on the dependence of the characteristic X-ray emission on the incident electron beam direction. A significant channeling effect was observed for slightly positive and negative excitations of the [100] reflection. The results indicate that for the composition (Ba0, 85Ca0.15O)1.02TiO2.00, a substantial fraction of the total calcium (> 20%) occupies Ti sites.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 31: Symposium N – Electron Microscopy of Materials , 1983 , 345
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1a. Spence, J.C.H. and Taft, J., Scanning Electron Microscopy, Vol. II, SEM Inc., 523–531 (1982).Google Scholar
1b. Spence, J.C.H. and Taft, J., J. Micros. 130, 147–154 (1983).CrossRefGoogle Scholar
2. Appleby, J., Han, Y.H. and Smyth, D.M., 85th Ann. Meeting of the American Ceramic Society, Chicago, April 25, Abstract 13–E–83 (1983).Google Scholar
3. Lal, M., Harmer, M.P. and Smyth, D.M., to be presented at the 86th Ann. Meeting of the American Ceramic Society, Pittsburgh, May 1984.Google Scholar
4. Chan, N.H., Sharma, R.K. and Smyth, D.M., J. Electrochem. Soc. 128, 1762–1769 (1981).Google Scholar
5. Romig, A.D. Jr. and Goldstein, J.I., Met. Trans A. 11A, 1151 (1980).Google Scholar
6. Taft, J., Z. Naturforsch 34a, 452 (1979).Google Scholar