Cole-Davidson fitting parameters β and τ for as-deposited CeO2 samples with different grain sizes. It is clear that the trend of beta increases from 6.13 nm, peaks at 8.83 nm with the beta value of 0.21, and then descends. The trend of tau decreases from 6.13 to 23.62 nm. Therefore, the trend of beta is consistent with the deteriorative degree of dielectric relaxation. The inset shows the relationship between the Cole-Davidson fitting parameters (beta and tau) and the grain size values for the Nd-doped PNZT samples (data from ). The trend of beta (the deteriorative degree of dielectric relaxation) rises from 12.1 nm, peaks at 22.5 nm with the beta value of 0.03, and then declines within the range of 22.5 to 25 nm. The trend of tau decreases from 12.1 to 25 nm accordingly, similar to the CeO2 samples.
Zhao et al. Nanoscale Research Letters 2013 8:172 doi:10.1186/1556-276X-8-172