Structural and dielectric properties of BaTiO3 - BiScO3 ceramics

Abstract

The structural and dielectric properties of bulk (1-x) BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -x BiScO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (x = 0 - 0.6) ceramics were investigated to acquire a better understanding of the binary system, including determination of the phase diagram, dielectric properties, and the difference in roles of Bi and BiScO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> doping on BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . The solubility limit for BiScO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> into the BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> perovskite structure was determined to be about x = 0.4, which was much higher than the solubility of Bi alone. A structural change from tetragonal to pseudocubic was observed at about x = 0.05 - 0.1 at room temperature. Dielectric measurements revealed the gradual change from typical ferroelectric behavior in pure BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> to a highly diffusive and dispersive relaxor behavior from 10 to 40 mol% BiScO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . Several of the compositions showed high permittivities (approximately 1000) with low temperature coefficients of capacitance.