Electrical properties of SrBi 2(Nb 0.7V 0.3) 2O 9− δ in the SrO–Bi 2O 3–0.7Nb 2O 5–0.3V 2O 5–Li 2B 4O 7 glass system

Abstract

Glasses in the system (100 − x)Li 2B 4O 7– x(SrO–Bi 2O 3–0.7Nb 2O 5–0.3V 2O 5) (where x = 10, 30 and 50, in molar ratio) were fabricated via melt quenching technique. The compositional dependence of the glass transition ( T g) and crystallization ( T cr) temperatures was determined by differential thermal analysis. The as-quenched glasses on heat-treatment at 783 K for 6 h yielded monophasic crystalline strontium bismuth niobate doped with vanadium (SrBi 2(Nb 0.7V 0.3) 2O 9− δ (SBVN)) in lithium borate (Li 2B 4O 7 (LBO)) glass matrix. The formation of nanocrystalline layered perovskite SBVN phase was preceded by the fluorite phase as established by both the X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The dielectric constants for both the as-quenched glass and glass–nanocrystal composite increased with increasing temperature in the 300–873 K range, exhibiting a maximum in the vicinity of the crystallization temperature of the host glass matrix. The electrical behavior of the glasses and glass–nanocrystal composites was characterized using impedance spectroscopy.