Accession Number : AD0736797

Title :   Measurement of the Elastic, Piezoelectric, and Dielectric Constants of Bi12GeO20.

Descriptive Note : Physical sciences research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Slobodnik,A. J. , Jr. ; Sethares,J. C.

Report Date : 10 NOV 1971

Pagination or Media Count : 31

Abstract : The low acoustic velocity of bismuth germanium oxide (Bi12GeO20) has made it an attractive delay line material for achieving long time delays in short spaces. To resolve conflicting published results concerning the values of the elastic, piezoelectric, and dielectric constants of Bi12GeO20, an exhaustive study of the material was made. Over 45 samples of material grown by 3 independent sources were tested. The basic technique adopted for determining the elastic and piezoelectric coefficients involved the frequency measurement of acoustic resonances of thin plates. Since the largest discrepancy between two previous series of measurements was in the value of the piezoelectric constant, this coefficient was determined using three different methods. The first accurate determination of the dielectric constant of Bi12GeO20 at microwave (2 to 4 GHz) frequencies was made by measuring the frequency of a low order TE electromagnetic mode of a disk resonator placed between two semi-infinite conducting planes. A listing of the computer program relating theory and experiment for this measurement is provided. (Author)

Descriptors :   (*BISMUTH COMPOUNDS, PHYSICAL PROPERTIES), GERMANIUM COMPOUNDS, OXIDES, CRYSTALS, ELASTIC PROPERTIES, DIELECTRIC PROPERTIES, PIEZOELECTRIC EFFECT, TEST METHODS, COMPUTER PROGRAMS, DELAY LINES

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE