High temperature Raman spectra and micro-structure of KTN crystal and melt

The high temperature Raman spectra of KTN crystal and melt were studied. The structures of KTN crystal and melt were analyzed. The rule of structure change of KTN crystal with increasing temperature was analyzed. The results show that the peaks of spectra move to the lower wavelength and broaden by different degrees. The intensities of spectra peaks decrease, too. Raman peaks at 539, 585, 835, 868 and 875 cm(-1) were analyzed in detail. Phase transition from tetragonal to cubic was observed and explained. In high temperature KTN melt, the [Ta/NbO6] octahedron entities disappeared. Meanwhile, there were many Ta/Nb=O double bonds in the [Ta/NbO3](-) entities. It showed that there were [Ta/NbO3](-) growth unities in KTN melts.