Accession Number:

ADA164793

Title:

Electrical Measurements on Alpha-Quartz Crystals.

Descriptive Note:

Final technical rept. Nov 81-Dec 84,

Corporate Author:

HENRY KRUMB SCHOOL OF MINES NEW YORK

Personal Author(s):

Report Date:

1985-12-01

Pagination or Media Count:

53.0

Abstract:

This study was aimed at achieving a better understanding of the defects in alpha-quartz crystals that affect their frequency stability. The principal techniques used were electrical conductivity and dielectric loss measurements, both of which are largely controlled by alkalis present to compensate for substitutional Al3. In order to deal with just one alkali species at a time, samples studied were swept with either Li or Na. The results involve considerable information about Al-Na and Al-Li bound pairs in the crystal, about alkalis freed from these pairs that give rise to the conductivity, and about the defects which include electrons and holes produced by X-ray irradiation of these crystals. The Al-Na pairs can exist in two configurations alpha and beta with the Sodium on opposite sides of the AlO4 tetrahedron, off the C2 symmetry axis. In Aluminum-Lithium, however, the Li sits on the C2 axis. The alkalis freed at high temperature give rise to the conductivity and involve a higher activation energy for Li and for Na. Finally, upon irradiation, liberated alkalis form new centers which produce a striking low-temperature dielectric loss peak. The use of computer simulation calculations has also been shown to be a helpful adjunct to the electrical measurements.

Subject Categories:

  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE