Processing and characterization of lead magnesium tantalate ceramics

摘要: Using a processing route that employed closed platinum crucibles, single phase ceramics of Pb(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} (PMT) relaxor ferroelectrics were prepared with densities greater than 95{percent} their theoretical value. The improvements in the sintering characteristics this system result from reflected by dielectric properties, {epsilon}{sub max}{sup {prime}}=6300 at 182 K, which are similar to those reported for crystal PMT. Contrast originating nanosized polar clusters was evident dark-field TEM images collected PMT room temperature and showed little change upon cooling through permittivity maximum. electron diffraction patterns contained weak superlattice reflections (h{plus_minus}1/2, k{plus_minus}1/2, l{plus_minus}1/2) originate 1:1 ordering B-site cations. High resolution imaging indicated lengthscale chemical is essentially identical niobate relaxors such as PMN, 1{endash}2 nm ordered domains being surrounded disordered matrix. {copyright} {ital 1997 Materials Research Society.}