Abstract
Pulsed current‐voltage measurements have been carried out on thin films of 
varying in thickness from 1000 to 10.000Aå. The I–V data fit a relationship of the form 
normally associated with ionic conduction. If it is assumed that the internal field is equal to the externally applied field, the derived ionic jump distance is of the order of 20Aå. However, potential probe measurements show a strong concentration of positive space charge near the cathode. When the effect of the space charge on the internal electric field is accounted for, a smaller value is obtained for the ionic jump distance, which is more in agreement with the crystal structure of 
.