Unusual structural-disorder stability of mechanochemically derived-Pb(Sc0.5Nb0.5)O3

This study demonstrates the important effect of processing on the B-site ordering in Pb(Sc0.5Nb0.5)O-3 ceramics. In contradiction to previous observations on ceramics prepared from solid state synthesis powders, which show a distinctive B-site cation ordering when annealed below similar to 1200 degrees C, in mechanochemically derived ceramics sintered 200 degrees C below this temperature, we do not observe such ordering, regardless of the conditions of thermal post-annealing. Accordingly, atomic-scale transmission electron microscopy revealed nanometer-sized B-site ordered regions in mechanochemically derived ceramics contrary to the larger regions extending through the whole grains in solid-state derived ceramics.