  Pb(Mg1/3Nb2/3)O3-PbTiO3 solid solution (PMN(1-x)-PTx) ceramics with 0 <x<1
have been prepared by homo-epitaxial templated grain growth (HTGG) using cubic
PMN-PT single crystal seeds as templates and nanoparticles for thes ceramic
matrix. Samples were prepared using the doctor Blade method and sintered in a
controlled atmosphere. They were then analysed by DTA, TGA, optical/scanning
electron microscopy, Raman spectroscopy and imaging. Relationships between
Raman parameters such as band component or area versus composition (x) are
proposed. Wavenumber and peak area shifts from the single crystal seed centre
to periphery growth are assigned to compositional change. Representative medium
to highly textured ceramics with Lotgering factors of ~0.7 and 0.9 were
sintered at 1150 degrees C and 1200 degrees C, respectively, and studied by
direct and smart Raman imaging. The Raman peak centre of gravity depends on the
solid solution composition whereas peak intensity is correlated to the
unit-cell distorsion and related short-range structure. Two different growth
mechanisms are observed: below ~1200 degrees C, sharp corner and straight edged
single crystal seeds develop through a liquid I phase at the crystal/matrix
interface; at higher temperatures, the matrix is consumed and crystal growth
develops in contact with a liquid II phase, through the help of the high PbO
partial pressure. Smart Raman imaging shows that the final composition and
structure is very close to that of the matrix. Formation of short-range ordered
B/B' domains is expected. A phase diagram is proposed.

Materials Science