Composites of 0.9Pb(Mg1/3Nb2/3)O-3-0.1PbTiO(3) prepared by a sol-gel method: effect of atmosphere powders

Dielectric and electrical properties of relaxer ferroelectric 0.9PMN-0.1PT ceramics prepared by a sol-gel method were investigated as a function of Pb ZrO3 atmosphere powders. The proper amount of atmosphere powders led to bet ter properties of dielectric constant, polarization, and strain by preventi ng PbO volatilization from ceramics. Excessive amount of atmosphere powder, however resulted in aging characteristics such as decreases in dielectric constant and loss exhibiting saddle-shaped dielectric constant and loss vs. temperature curves. A propeller-shaped P-E hysteresis curve indicating agi ng characteristics was also observed when an excessive amount of atmosphere powder was used during sintering. The aging of ceramics caused by absorpti on of PbO into the ceramics resulted in decreased polarization and strain. These aging characteristics associated with defects by excessive PbO absorp tion could not be reversed even though the aged ceramics underwent a heat-t reatment above the dielectric maximum temperature. (C) 1999 Kluwer Academic Publishers.