Ion polarizability additivity rule and its application on HTSC substrate materials

An ion polarizability additivity rule (R. D. Shannon)1 was applied to calculate the dielectric constants of a large family of substrate materials (for HTSC films) and to compare with the measured dielectric constant values. The applicability and the limitations of the model were examined in light of experimental results of new substrate materials. The suitability and the limitations of the ion polarizability additivity rule in predicting dielectric constants of ionic materials were discussed. Possible causes of discrepancies found between the calculated and experimental values of the dielectric polarizabilities and dielectric constants were examined and modifications on the current additivity approach were proposed.