Nano-Phased Crystallisation of Ferroelectrics from Glasses in the K2O-TiO2-P2O5 and K2O-Nb2O5-SiO2 Systems.

Crystallisation behaviour of glasses in the K2O-TiO2-P2O5 (KTP) has been studied by DTA, XRD, EM and SHG techniques to isolate composition ranges where bulk precipitation of ferroelectric phase KTiOPO4 occurs. It was found that bulk crystallisation of KTiOPO4 at temperatures slightly exceeding Tg is initiated by addition of SiO2. Controlled heat treatment leads to formation of optically non-linear KTiOPO4 nano-particles in KTP glasses (like amorphous nanostructuring in KNS glasses) in initial stages of phase separation and produces nanoscaled modulation of polarisability and SHG effect. The results are compared to the xK2O xNb2O5(1-2x)SiO2 (KNS) systems. [ABSTRACT FROM AUTHOR]