Synthesis, Ferroelectric and Electrooptic Properties of Transparent Crystallized Glasses with Sr_xBa_(1-x)Nb_2O_6 Nanocrystals

摘要

Crystallized glasses consisting of Sr_xBa_(1-x)Nb_2O_6 (SBN) nanocrystals (x = 0.5, 0.61, and 0.62) with a tetragonal tungsten-bronze structure are synthesized using a conventional glass crystallization technique in xSrO-(32-x)BaO-32Nb_2O_5-36B_2O_3 glasses with x = 16, 19.5, and 24. Nanocrystals of Sr_(0.5)Ba_(0.5)Nb_2O_6, Sr_(0.61)Ba_(0.39)Nb_2O_6, and Sr_(0.62)Ba_(0.38)Nb_2O_6 are found to have rod-like shapes with an average diameter of 20-40 nm as determined from X-ray diffraction analyses and transmission electron microscope observations and to exhibit ferroelectricities as deduced from the presence of hysteresis in polarization-electric field curves. Although the optical transparency of crystallized glasses in the visible region decreases along with the formation of SBN nanocrystals, optical transparencies (sample thickness: ～1 mm, transmittance: ～80%) are observed at the wavelength of 1.55 μm. Electrooptic activity was confirmed for the crystallized glasses with SBN nanocrystals, indicating that the present study would be a step for active optical device applications in glass-related materials consisting of SBN nanocrystals.