Polarization in thorium oxide crystals

✍ Scribed by W.E. Danforth; J.H. Bodine

• Publisher: Elsevier Science
• Year: 1955
• Tongue: English
• Weight: 563 KB
• Volume: 260
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(55)90190-3

✦ Synopsis

Studies have been made of the electrical polarization resulting from the passage of current in single crystals of low-oxygen thorium oxide at elevated temperatures . The emf . across the crystal necessary to maintain a constant current rises by a factor of 100 and more during the establishment of the final equilibrium. Because of the wide ranges of time involved, observations were required with oscillographic techniques as well as long time measurements using a slide wire potentiometer . The resistivity of the material was found to vary from 6000 ohm-cm . at 900° C . to 400 o hm-cm . a t 1300° C., and to be unchanged by large values of polarization . Indications point to a critical potential for the onset of electrolysis in the neighborhood of 0 .3 volt. The dependence of initial conductance upon temperature point to an activation energy for the initial conductance of 1 .1 e-volts and the same temperature dependence is approximately valid over the whole polarization curve . Theoretical considerations indicate that ions and electrons are both mobile and, to account for the high polarization ratios, it appears that the fraction of current carried by the electrons is less than 1 per cent of the total .

A . INTRODUCTION