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THE NONLINEARITY IN THE ELECTRICAL CONDUCTIVITY OF SODIUM-CHLORIDE
Abstract
The deviation from Ohm's law in the electrical con-ductivity of NaC! crystals has been measured in the tempera- ture range 240°C to 540°C. With an applied field consisting of two sinusoidal components, the term in the current density cubic In the electric field was determined by measuring an appropriate combination frequency component in the total current. Using an electric field of 2000 volt/cm, with frequencies of the order of 1000 cps, the current resulting from the cubic term in the field was 0.001% of the total current, about 1000 times larger than predicted by the simple. theory of lonic conductivity. It is thought that the ob- served nonlinearity was associated with the motion of fons as opposed to an electrode effect or electron current because: 1) The temperature dependence of the cubic term was roughly the same as that of the linear part of the lonic conductivity. The temperature range of the work Included parts of both the low temperature and Intrinsic conductivity regions. 2) The nonlinearity was insensitive to the metal used for electrodes as well as to variations in the state of the electrode-salt contact. 3) The nonlinear component of the total current varfed Inversely as the cube of the crystal thickness. 4) The nonlinear current was Insensi- tive to the presence or absence of visible light.At the lower temperatures the nonlinear current de- creased as the frequencies of the applied field increased, Indicating that the observed nonlinearity was not character- Istic of a bulk fonic conductivity but rather, possibly, the result of inhomogenelties internal to the crystal.The cubic term in the electric current In LIF and KCI was also measured; the results obtained were similar to those for NaCl. The cubic term was again nearly a factor of 1000 larger than predicted by the simple theory.The observatione are basically unexplained. The assumption of Internal charge blocking boundaries would appear, however, to offer a possible qualitative explanation for the observations.
Subject Area
Condensed matter physics
Recommended Citation
SKOV, CHARLES ELMAN, "THE NONLINEARITY IN THE ELECTRICAL CONDUCTIVITY OF SODIUM-CHLORIDE" (1963). ETD collection for University of Nebraska-Lincoln. AAI6304783.
https://digitalcommons.unl.edu/dissertations/AAI6304783