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Sluggish Transition Between Tetragonal and Rhombohedral Phases of Pb(Zr,Ti)O, 515of the narrow composition ranges investigated. Such results have, however, been reported for anion-excess fluorites by Kucheria and BerardZ6 and in anion-excess C-type rare earth oxide by Scheidecker and Berard." In the latter study, the activation energy for Hf impurity diffusion in undoped ErZO, is even larger (i.e. 986240 kl-mol-') than those found in the present study, a result in general agreement with the data of Schiavi" (i.e. 875+ 188 kl-mol-') derived from interdiffusion coefficient measurements on the same phase.The grain-boundary coefficient data (Table 111) are not extensive and are seen to range between lo3 and lo' times the volume coefficients. Perhaps the most interesting observation regarding the grain-boundary coefficients is that they too exhibit very large activation energies (Table III) which, in the case of Er, are of about the same magnitude as those for volume coefficients. The single activation energy determined for Hf is considerably smaller than those for Er, but still is quite large for grain-boundary coefficients.

Hatano, J.; Takahashi, K.; and Tokumoto, H., "Domain structure and polarization reversal in ferroelectrics studied by atomic force microscopy" (2005 The ferroelectric domain structure and its dynamics under applied electric field have been studied with nanoscale resolution by atomic force microscopy ͑AFM͒. Two mechanisms responsible for the contrast between opposite domains are proposed: large built-in domains are delineated in friction mode due to the tip-sample electrostatic interaction, and small domains created by an external field are imaged in topography mode due to piezoelectric deformation of the crystal. The ability of effective control of ferroelectric domains by applying a voltage between the AFM tip and the bottom electrode is demonstrated. It is experimentally confirmed that the sidewise growth of domain proceeds through the nucleation process on the domain wall.