Defects and oxide ion transport properties in the substituted Zn2TiO4

Electric conductivities of Zn2−x/2Ti1−xTaxO4 have been measured at 900°C in the oxygen partial pressure range of 1 to 10−13 atm, in order to estimate the ionic conduction separately from the electronic one. The obtained ionic conductivities were in good agreement with the products of electric conductivities and tion by oxygen gas concentration cells, which grew exponentially with the cation vacancy concentration in this system. Dielectric relaxation experiments on Zn2−(x−y)/2Ti1−(x+y)TaxAlyO4 system revealed that ionic diffusion process varied gradually from the oxide ion vacancy mechanism to the interstitialcy diffusion with increasing extrinsic cation vacancy concentration.