Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study
The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific poin...
Main Authors: | , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2020-08-01
|
Series: | Materials |
Subjects: | |
Online Access: | https://www.mdpi.com/1996-1944/13/16/3513 |
id |
doaj-72221e3b42ee4f53914a0798751bbfd7 |
---|---|
record_format |
Article |
spelling |
doaj-72221e3b42ee4f53914a0798751bbfd72020-11-25T03:25:46ZengMDPI AGMaterials1996-19442020-08-01133513351310.3390/ma13163513Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative StudyVassilios Saltas0Despoina Pentari1Filippos Vallianatos2Institute of Physics of the Earth’s Interior and Geohazards, Hellenic Mediterranean University Research Center, 73100 Chania, GreeceLaboratory of Inorganic and Organic Geochemistry and Organic Petrography, Department of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, GreeceInstitute of Physics of the Earth’s Interior and Geohazards, Hellenic Mediterranean University Research Center, 73100 Chania, GreeceThe unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10<sup>−2</sup> Hz to 10<sup>6</sup> Hz) and temperatures (473–1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33–0.83 eV for biotite and 0.69–1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe.https://www.mdpi.com/1996-1944/13/16/3513micabiotitemuscoviteimpedance spectroscopyelectrical conductivityelectric modulus |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Vassilios Saltas Despoina Pentari Filippos Vallianatos |
spellingShingle |
Vassilios Saltas Despoina Pentari Filippos Vallianatos Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study Materials mica biotite muscovite impedance spectroscopy electrical conductivity electric modulus |
author_facet |
Vassilios Saltas Despoina Pentari Filippos Vallianatos |
author_sort |
Vassilios Saltas |
title |
Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study |
title_short |
Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study |
title_full |
Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study |
title_fullStr |
Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study |
title_full_unstemmed |
Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study |
title_sort |
complex electrical conductivity of biotite and muscovite micas at elevated temperatures: a comparative study |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2020-08-01 |
description |
The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10<sup>−2</sup> Hz to 10<sup>6</sup> Hz) and temperatures (473–1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33–0.83 eV for biotite and 0.69–1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe. |
topic |
mica biotite muscovite impedance spectroscopy electrical conductivity electric modulus |
url |
https://www.mdpi.com/1996-1944/13/16/3513 |
work_keys_str_mv |
AT vassiliossaltas complexelectricalconductivityofbiotiteandmuscovitemicasatelevatedtemperaturesacomparativestudy AT despoinapentari complexelectricalconductivityofbiotiteandmuscovitemicasatelevatedtemperaturesacomparativestudy AT filipposvallianatos complexelectricalconductivityofbiotiteandmuscovitemicasatelevatedtemperaturesacomparativestudy |
_version_ |
1724595917475020800 |