Time domain response and the data analysis of ferroelectric discharge current

The time domain method is more reliable for the study of nonlinear dielectric response compared with frequency domain analysis. A Tikhonov regularization method, which is widely adopted for ill-posed problem, is described for derivation of the relaxation time distribution function, g(τ), from the ferroelectric discharge current in time domain. The new method allows study of the structure variation and the relaxation behavior of ferroelectrics at different temperatures. For barium stannate titanate ceramics (BTS20), g(τ) has been successfully derived; the relaxation peaks move to shorter times with increasing temperature in the range 20–60°C, which may indicate a space charge thermal activation process. However, g(τ) could not be derived from the discharge current by the regularization method for BTS20 at temperatures above 60°C or for lanthanum-doped lead zirconium titanate transparent ceramic (PLZT), since the data do not satisfy the discrete Picard condition, which is a valid criterion for regularization method.