Microstructures and Dielectric Properties of Ferroelectric Glass‐Ceramics

Abstract

The microstructures of ferroelectric glass‐ceramics derived from (Pb,Sr,Ba)Nb2O6 solid solutions have been investigated systematically using electron microscopy (TEM, SEM) and X‐ray diffraction (XRD). These data, together with the measured dielectric properties of the materials, have been correlated with both the sintering/devitrification conditions and compositional changes to the base glass. The low incidence of ferroelectric domains suggests that an increase in permittivity results from an increase in internal stress during grain growth. These domains were observed only in a few tetragonal structured crystals with grain sizes >1 μm. Their compositions were typically Sr‐rich and Ba‐depleted. For a given devitrification/crystallization temperature, the grain compositions and sizes are affected significantly by relatively minor compositional changes to the base glass network formers. The diffuse temperature dependence of permittivity is attributed to the fine‐grain (submicrometer) microstrucutres and the compositional range of solid solutions which arise during devitrification.

Crystallization and dielectric properties of borate-based ferroelectric PbTiO3 glass-ceramics

“…Studies relating to nucleation of high-permittivity ferroelectric crystals in glasses have been carried out since the early 1960s. Ferroelectric crystalline phases investigated include SrTiO 3 [5], BaTiO 3 [6,7], LiTaO 3 [8], LiNbO 3 [8,9], NaNbO 3 [10], PbTiO 3 (PT) [11][12][13] and (Pb,Sr,Ba)Nb 2 O 6 [14]. Exploitation of pyroelectric, piezoelectric and/or electro-optic properties has been limited mainly due to difficulty in poling these materials.…”

Dielectric Properties of Niobate Glass Ceramics of PbO-SrO-Na2O-Nb2O5-SiO2 System with Partial Substitution of K+ for Na+

“…They have attempted to refine the composition of the crystal phase, the crystal size, microstructure, optimize the proportion of glass and ceramic phase, and many other methods to improve the dielectric constant and dielectric breakdown strength. [7][8][9][10][11][12][13][14][15] This study was driven by the motivation of investigating the effects of the crystallization process and the associated dielectric properties of PbO-SrO-Na 2 O-Nb 2 O 5 -SiO 2 system from substitution of K 2 O for Na 2 O content.…”

EFFECT OF Ti ON THE OPTICAL BAND GAP OF FERROELECTRIC BaTixO5-BASED BULK GLASS

“…a glass fabricated from ferroelectric materials, is quite a promising material for applications in the field of optics and electronics because of its potentially high dielectric constant, ferroelectricity, nonlinear optics and so on. [1][2][3][4][5][6] However, prior to any technological application the quality of the materials has remained a major challenge for both researchers and engineers who faced serious difficulties in fabricating the materials of good quality. For example, LiNbO 3 glass, PbTiO 3 glass and Bi 4 Ti 3 O 12 glass could only be prepared in the form of thin ribbon using the twin roller quenching technique, [7][8][9] which were brittle and poor in quality and therefore, were not suitable both for applied and fundamental research.…”