High temperature conductivity studies on nanoscale yttria-doped zirconia thin films and size effects

Thin films of 9.5% yttria-doped zirconia in the range of 17-210 nm thickness were deposited on MgO (100) substrates by electron beam evaporation. The conductivity of the films was found to increase as the film thickness decreased. The films were found to be a mixture of both cubic and tetragonal phases. The impedance and electrical modulus parameters indicate that the relaxation process is due to ionic conduction. Enhancements in conductivity are attributed to the space charge effects that occur at the interface and grain boundaries as evidenced by the high activation energy observed in the conductivity relaxation process. (c) 2006 American Institute of Physics.