Abstract: KTaO₃ ceramic with excellent dielectric properties has been made by hot isostatic pressing (HIP).
In order to study the nonlinear properties of KTaO₃ ceramic at low temperature, we measured the electric-field dependence of dielectric constant under bias field up to 16 kV/cm and between temperatures from 4.2 K to 100K.
It was found that dielectric constant depends on the bias field at temperatures below 60K and the nonlinearity of dielectric response rises strikingly with decreasing temperature. It is related to the incipient ferro-electricity of KTaO₃ ceramic at low temperature.
We evaluated the values for nonlinear dielectric response coefficients of KTaO₃ ceramic while the Devonshire model was used to fit the experimental data. The values were compared with that of the nonlinear dielectric response cofficients of KTaO₃ single crystal which had previously been obtained by both measuring dielectric constants and the phonon frequencies of transverse optical modes in the presense of bias fields.