Electric and dielectric properties of forsterite between 400 and 900°C |
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| Authors: | P Abelard JF Baumard |
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| Institution: | 1. Laboratoire de Géochimie, Minéralogie, Université d''Orléans, 45045 Orléans Cédex France;2. Centre de Recherches sur la Physique des Hautes Températures, C.N.R.S., 45045 Orléans Cédex France |
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| Abstract: | The electrical impedance of a sintered forsterite sample containing 1 mol percent SiO2 in excess has been studied as a function of frequency (1–105 Hz) and temperature (400–900°C). The electrical properties are strongly frequency-dependent, requiring both conduction and displacement current for their interpretation. The electrical conductivity is thermally activated with a mean activation energy of 1.15 eV. It is interpreted as being ionic and caused by migration of magnesium ions via a vacancy mechanism. Dielectric data deduced from impedance measurements vary as ωn?1 (0 < n < 1) at constant temperature. The value of n is different below and above a critical frequency ωc, which is thermally activated and interpreted as the jump frequency of the migrating species. |
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