start-ver=1.4
cd-journal=joma
no-vol=122
cd-vols=
no-issue=1
article-no=
start-page=158
end-page=171
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2017
dt-pub=20170114
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Pressure dependence of electrical conductivity in forsterite
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract= Electrical conductivity of dry forsterite has been measured in muli-anvil apparatus to investigate the pressure dependence of ionic conduction in forsterite. The starting materials for the conductivity experiments were a synthetic forsterite single crystal and a sintered forsterite aggregate synthesized from oxide mixture. Electrical conductivities were measured at 3.5, 6.7, 9.6, 12.1, and 14.9 GPa between 1300 and 2100 K. In the measured temperature range, the conductivity of single crystal forsterite decreases in the order of [001], [010], and [100]. In all cases, the conductivity decreases with increasing pressure and then becomes nearly constant for [100] and [001] and slightly increases above 7 GPa for [010] orientations and a polycrystalline forsterite sample. Pressure dependence of forsterite conductivity was considered as a change of the dominant conduction mechanism composed of migration of both magnesium and oxygen vacancies in forsterite. The activation energy (ΔE) and activation volume (ΔV) for ionic conduction due to migration of Mg vacancy were 1.8–2.7 eV and 5–19 cm3/mol, respectively, and for that due to O vacancy were 2.2–3.1 eV and −1.1 to 0.3 cm3/mol, respectively. The olivine conductivity model combined with small polaron conduction suggests that the most part of the upper mantle is controlled by ionic conduction rather than small polaron conduction. The previously observed negative pressure dependence of the conductivity of olivine with low iron content (Fo90) can be explained by ionic conduction due to migration of Mg vacancies, which has a large positive activation volume.
en-copyright=
kn-copyright=

en-aut-name=YoshinoTakashi
en-aut-sei=Yoshino
en-aut-mei=Takashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=ZhangBaohua
en-aut-sei=Zhang
en-aut-mei=Baohua
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=RhymerBrandon
en-aut-sei=Rhymer
en-aut-mei=Brandon
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=ZhaoChengcheng
en-aut-sei=Zhao
en-aut-mei=Chengcheng
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=FeiHongzhan
en-aut-sei=Fei
en-aut-mei=Hongzhan
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

affil-num=1
en-affil=Institute for Planetary Materials, Okayama University
kn-affil=

affil-num=2
en-affil=Key Laboratory for High-Temperature and High-Pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences
kn-affil=

affil-num=3
en-affil=Department of Geosciences, State University of New York at Stony Brook
kn-affil=

affil-num=4
en-affil=Institute for Planetary Materials, Okayama University
kn-affil=

affil-num=5
en-affil=Bayerisches Geoinstitut, University of Bayreuth
kn-affil=
END