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Minimization of Parasitic Currents in High‐Temperature Conductivity Measurements on High‐Resistivity Insulators
Author(s) -
Will Fritz G.,
Janora Kevin H.
Publication year - 1992
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/j.1151-2916.1992.tb05507.x
Subject(s) - electrical resistivity and conductivity , torr , conductivity , materials science , leakage (economics) , insulator (electricity) , analytical chemistry (journal) , atmospheric temperature range , electrode , optoelectronics , electrical engineering , chemistry , thermodynamics , physics , macroeconomics , chromatography , economics , engineering
An experimental setup and novel measurement technique are described which allow reliable conductivity measurements to be made at conductivities as low as 10 −17 Ω −1 .cm −1 and temperatures up to at least 1300°C. This capability is of particular interest for conductivity measurements on high‐resistivity insulators over a large range of temperatures. This technique has been used to measure the conductivity of single‐crystal alumina from 400° to 1300°C in a 10 −7 torr (∼1.3 × 10 −5 Pa) vacuum, equivalent to an oxygen partial pressure of about 10 −8 torr (∼1.3 × 10 −11 atm or ∼ 1.3 × 10 −6 Pa). Surface and gas‐phase conductance are determined as a function of temperature, and the requirements for their minimization are described. A key requirement is a very low voltage between the volume guard and the guarded electrode. The effect of leakage currents due to the sample fixture, electrical feedthroughs, and electronic instrumentation are also evaluated, and proper design features to make these effects negligible are outlined.