Details
| Original language | English |
|---|---|
| Pages (from-to) | 365-373 |
| Number of pages | 9 |
| Journal | Physics and chemistry of minerals |
| Volume | 24 |
| Issue number | 5 |
| Publication status | Published - Jul 1997 |
Abstract
Measurements of the real part of conductivity (σ′) and dielectric function (ε′) were performed on large crystal flakes of biotite (Moen) and vermiculite (Benahavis), at variable frequencies (0.1 to 1000 kHz) and as a function of temperature (300 K<T<900 K). By heating, cooling and repeated heating experiments under inert atmospheric conditions effects involving water (H2O) diffusion and electrical transport were separated. The effect of dehydration dominates the functional dependence of ε′ T at frequencies below about 100 kHz, within the first heating run. Six dehydration steps for vermiculite Benahavis and two broad features for biotite Moen are observed, the water being transported effectively only in the interlayers. Electrical transport occurs along Fe paths within the octahedral layers and can be described by σ′=σdc + A · ws. Values of s are between 0.45 and 0.8. σdc shows a temperature dependence according to exp(-Ea(T)/kT) with Ea(T) between 0.3 and 0.6 eV. Ea is suggested to be composed of a polaron plus disorder contribution.
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Physics and chemistry of minerals, Vol. 24, No. 5, 07.1997, p. 365-373.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Dielectric properties of iron-bearing trioctahedral phyllosilicates
AU - Rüscher, C. H.
AU - Gall, S.
PY - 1997/7
Y1 - 1997/7
N2 - Measurements of the real part of conductivity (σ′) and dielectric function (ε′) were performed on large crystal flakes of biotite (Moen) and vermiculite (Benahavis), at variable frequencies (0.1 to 1000 kHz) and as a function of temperature (300 K2O) diffusion and electrical transport were separated. The effect of dehydration dominates the functional dependence of ε′ T at frequencies below about 100 kHz, within the first heating run. Six dehydration steps for vermiculite Benahavis and two broad features for biotite Moen are observed, the water being transported effectively only in the interlayers. Electrical transport occurs along Fe paths within the octahedral layers and can be described by σ′=σdc + A · ws. Values of s are between 0.45 and 0.8. σdc shows a temperature dependence according to exp(-Ea(T)/kT) with Ea(T) between 0.3 and 0.6 eV. Ea is suggested to be composed of a polaron plus disorder contribution.
AB - Measurements of the real part of conductivity (σ′) and dielectric function (ε′) were performed on large crystal flakes of biotite (Moen) and vermiculite (Benahavis), at variable frequencies (0.1 to 1000 kHz) and as a function of temperature (300 K2O) diffusion and electrical transport were separated. The effect of dehydration dominates the functional dependence of ε′ T at frequencies below about 100 kHz, within the first heating run. Six dehydration steps for vermiculite Benahavis and two broad features for biotite Moen are observed, the water being transported effectively only in the interlayers. Electrical transport occurs along Fe paths within the octahedral layers and can be described by σ′=σdc + A · ws. Values of s are between 0.45 and 0.8. σdc shows a temperature dependence according to exp(-Ea(T)/kT) with Ea(T) between 0.3 and 0.6 eV. Ea is suggested to be composed of a polaron plus disorder contribution.
UR - http://www.scopus.com/inward/record.url?scp=0031466472&partnerID=8YFLogxK
U2 - 10.1007/s002690050050
DO - 10.1007/s002690050050
M3 - Article
AN - SCOPUS:0031466472
VL - 24
SP - 365
EP - 373
JO - Physics and chemistry of minerals
JF - Physics and chemistry of minerals
SN - 0342-1791
IS - 5
ER -