MORPHOTROPIC PHASE-BOUNDARY AND DIELECTRIC-PROPERTIES OF V2O5-CONTAINING LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.4) FERROELECTRICS

SrxBa1-xNb2O6 (0.2 less than or equal to x less than or equal to 0.4: SBN) ceramics were fabricated by pressureless sintering with the addit ion of V2O5 (1 mol%) which considerably accelerated grain growth. X-ra y diffraction analysis of elongated grains indicated that there is a m orphotropic phase boundary between x=0.25 (tetragonal) and x=0.225 (or thorhombic) in the SBN system. The sharpening of a ferroelectric phase transition peak was maximum at x=0.2. This corresponded to a cation d istribution in which the A(2)-sites in the tungsten bronze structure w ere fully occupied by Ba2+ ions. A phase transition temperature diagra m was developed for the present composition region.