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Voltage‐Dependent Bulk Resistivity of SrTiO 3 : Mg Ceramics
Author(s) -
Gil Escrig Lidon,
Prades Marta,
Beltrán Héctor,
Cordoncillo Eloisa,
Masó Nahum,
West Anthony R.
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13004
Subject(s) - electrical resistivity and conductivity , analytical chemistry (journal) , materials science , conductivity , grain boundary , dielectric spectroscopy , ceramic , biasing , mineralogy , chemistry , voltage , microstructure , electrode , electrochemistry , composite material , electrical engineering , chromatography , engineering
Single phase ceramics of composition Sr(Ti 1– x Mg x )O 3– x : 0 ≤ x ≤ 0.01 were prepared by sol–gel synthesis and characterized by X‐ray diffraction, scanning electron microscopy, impedance spectroscopy, and current–voltage measurements. The bulk and grain‐boundary conductivities increase on application of a small dc bias voltage in the range 3–200 V/cm and at temperatures in the range 150°C–800°C. A qualitatively similar increase in conductivity occurs on increasing P O 2in the surrounding atmosphere, which shows that conduction is p type. The conductivity increase is reversible on removal of the dc bias or on reducing P O 2and is not observed in undoped SrTiO 3 . It is an intrinsic property of the bulk material, differs from the voltage‐dependent effects observed with varistors and is attributed to changes in redox equilibria between oxygen species at the surface which cause changes in carrier concentration in the interior. A capacitive model of this low‐field dc bias effect is presented and compared with a memristive model of high field resistance degradation.