Synthesis, Processing and Dielectric Properties of Compositions in the Strontium Titanate:Strontium Zirconate Solid Solution System

摘要

The processing and dielectric breakdown behavior of compositions in the strontium titanate:strontium zirconate solid solution system have been examined. Because neither orthorhombic strontium zirconate nor cubic strontium titanate is ferroelectric or piezoelectric, these materials are not subject to strong electromechanical deformations that may contribute to dielectric breakdown. However, due to its incipient ferroelectric behavior, strontium titanate exhibits a relatively high dielectric constant. Secondarily, the cations (Sr~(2+), Zr~(4+)) in strontium zirconate exist in highly stable valence states. These attributes may be desirable in producing perovskite-based dielectrics having moderate dielectric constants and high breakdown strengths. SrZrO_3, SrTiO_3, and Sr(Zr_xTi_(1-x))O_3 powders have been synthesized using the Pechini method, and these powders were used to fabricate capacitors. The dielectric constant and average breakdown strength for SrZrO_3 were 40 and 650 V/mil whereas the corresponding values for SrTiO_3 were 378 and 550 V/mil.