FAILURE OF HEBB-WAGNER POLARIZATION MEASUREMENTS DUE TO DECOMPOSITION OF THE SAMPLE

A novel four point Hebb-Wagner-type polarization method is used to examine the possibility of the decomposition of a solid under polarization conditions. Experimental results for CuBr show that the applied voltage is linear in lnI (I = current) in agreement with previous two point Hebb-Wagner-type measurements. However, the partition of the voltage along the sample, as measured on the four electrodes, does not conform with the one expected for a current of holes nor for a current of electrons in a sample of which the composition is stable. However, by assuming that the sample decomposes, the experimental data can be explained. Further experiments of different nature are conducted to verify the decomposition explanation: (a) Two of the blocking electrodes are replaced by reversible copper electrodes; (b) a lengthy experiment is conducted to look for copper deposition; (c) the effect of a pressure change of the Ar atmosphere surrounding the sample, on the current, is examined. All experiments support the decomposition explanation. The direct product of the decomposition is atomic bromine and copper.