Broadband light-scattering spectroscopy on fractal and non-fractal relaxors
Abstract
We show the quasi-elastic light scattering (QELS) spectra of two groups of relaxors: the first group includes relaxors that exhibit glasslike low-temperature thermal conductivity and heat capacity, namely, Pb(Mg1/3Nb2/3)O3 (PMN), (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), Pb(Zr1/3Nb2/3)O3 (PZN), and (Na1/2Bi1/2)TiO3 (NBT). The other group consists of relaxors exhibiting a normal (crystal) temperature dependence of the thermal conductivity and heat capacity, namely, K1- x Li x TaO3 (KLT) and KTa1- x Nb x O3 (KTN). The crystals of the first group yielded self-similar (power-law) QELS spectra, indicating the existence of fractal networks/clusters of polar nanoregions, while those of the second group did not show any self-similarity in the QELS spectra. These results imply that the glasslike low-temperature thermal conductivity and heat capacity in relaxors can be attributed to the vibrational modes specific to fractal networks/clusters formed by polar nanoregions.
- Publication:
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Japanese Journal of Applied Physics
- Pub Date:
- October 2016
- DOI:
- 10.7567/JJAP.55.10TC06
- Bibcode:
- 2016JaJAP..55jTC06K