E. I. Du Pont de Nemours and Co., Inc., Central
Research and Development Department,
Experimental Station, Wilmington, DE 19880-0356, U.S.A.
Division of Geological and Planetary Sciences,
California Institute of Technology, Pasadena, CA 91125-2500,
U.S.A.
The dielectric constants and dielectric loss values of five
natural and three synthetic spinel single crystals were
determined at 1 MHz using a two-terminal method and empirically
determined edge corrections. The results are:
| Composition | k' | tand |
| Mg1.02Al1.98Fe0.01O4 | 8.355 | 0.0005 |
| Mg1.00Al1. 98Fe0.02O4 | 8.322 | 0.0007 |
| Mg1. 00Al1.99Fe0.02O4 | 8.203 | 0.0007 |
| Mg1 01Al1.9804 | 8.352 | 0.0005 |
| Mg0.97Al02.01Fe0.01O4 | 8.302 | 0.0005 |
| Mg1. 00A12.00O4 | 8.325 | 0.0008 |
| Mg1. 00A12.00O4 | 8.176 | 0.0005 |
| Mg0 415A12.39O4 | 8.572 | 0.0011 |
The agreement between measured dielectric polarizabilities as
determined from the Clausius-Mosotti equation and those
calculated from the sum of oxide polarizabilities according to
aD(mineral) =
åaD(oxides)
for this group of spinels ranges
from + 1.1 to + 3.2%, well above the agreement value of 0.5-1.0%
found for well-behaved oxides. Possible reasons for these
discrepancies are discussed.
Journal of the Physics and Chemistry of Solids, Vol. 52. No. 9. pp. 1055-1059. (1991 )