STUDY ON THERMAL CHARACTERIZATION OF ZN-DOPED KNBO3 CRYSTALS

Zn-doped KNbO3 (1 to 8 mol% ZnO in melt) crystals have been grown by t he Kyropoulos method. The composition of the 1% mol Zn-doped samples w as determined by electron probe microanalysis. The results show that t he crystals are no longer Nb-rich, but still contain some potassium va cancies. The thermal expansion results and Raman spectra of doped and undoped samples were compared. The doped samples' thermal expansion co efficients parallel to the (010) plane decrease compared to the undope d samples. Compared to the undoped samples, the doped crystal's Raman spectra bands move to higher wave numbers and their temperature depend ence decreases. For the Zn-doped KNbO3, the temperature dependence of the NbO6 octahedral distortion and Nb5+ displacement decrease, when co mpared to pure KNbO3.