Behavior of Stress-Induced Charges in Cement Containing Quartz Crystals
✍ Scribed by Matsuda, T. ;Yamanaka, C. ;Ikeya, M.
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 135 KB
- Volume
- 184
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
The recombination process of electric charges induced by stress release has been measured for cement samples embedded within quartz crystals to investigate the behavior of piezo-compensating charges in quartz-bearing rocks. The stress with a release constant t of sðtÞ ¼ Ds e Àt=t led to a theoretical pulse charge density qðtÞ ¼ a Dsfeq=ðt À eqÞg ðe Àt=t À e Àt=eq Þ, where a, e and q are the piezoelectric coefficient, permittivity and resistivity, respectively. The induced charges appeared on a sample measured with non-contacting electrodes depending on the number and orientation of synthetic quartz crystals, and two decay time constants of 0.25 and 2.5 s were obtained. The apparent piezoelectric coefficient for a sample with one piece of quartz was 1:0 Â 10 À15 C/N. However, the coefficients for samples with two pieces of quartz, which were arranged in the same or alternate directions, were 4:1 Â 10 À15 and 1:7 Â 10 À15 C/N, respectively. The behavior of piezo-compensating charges around quartz crystals in conductive cement suggests ferroelectric charge migration through the measurements of depolarization current.