Nonresonant hole burning spectroscopy of the relaxor ferroelectric PLZT

The polydispersive dielectric response of a lanthanum-modified lead zirconate titanate relaxor ferroelectric was studied using nonresonant hole burning (NHB) spectroscopy. The dynamic heterogeneity of this material was evidenced by the fact that it was possible to burn frequency-dependent spectral holes. The maximum position of the spectral holes depended on the square root of the pump frequency Ω. The refilling of the spectral holes was monitored subsequent to excitation using various pump frequencies. The refilling data could be collapsed onto a master curve by re-scaling them, again, using Ω^−0.5 as scaling factor. The refilling time was found to be much longer than the time scale addressed most by the pump process. This behavior underscores the importance of domain wall motions for the dielectric relaxation process.