Self Diffusion in Magnesium Oxide Under the Influence of Moderate Electric Fields in the Temperature Range of 1100-1250K
Abstract
Diffusion of oxygen and magnesium is studied in nominally pure MgO crystals for the temperature range of 1100-1250 K. A nuclear technique that uses the nuclear reaction ('18)O(p,(alpha))('15)N in the region of the resonant energy at 629 KeV, is used to measure ('18)O concentration profiles. Oxygen diffusion coefficients are determined. In addition, magnesium drift is determined with an electric field applied to the samples. Activation energy and pre -exponential values are calculated for both oxygen and magnesium diffusion. Values are obtained for the Mg('++) ionic transference number. These results are in good agreement with those expected by extrapolating higher temperature values. The effect of time, temperature, and electric field strength on the cation drift are reported. Also, the effects on diffusion by doping MgO with 1500 (mu)g/g chromium is determined; the results are consistent with the assumption that excess V(,Mg) are present due to trivalent impurities. Rutherford backscattering in the random and channeling modes are used as a complementary technique to study surface modification in MgO due to electric field.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1984
- Bibcode:
- 1984PhDT.......132M
- Keywords:
-
- MASS TRANSPORT;
- TRANSFERENCE NUMBERS;
- Physics: Condensed Matter