Surface structural distortions in relaxor ferroelectric single crystals

Single crystal relaxor-ferroelectrics are used as transducers in a wide range of applications including medical ultrasound imaging, underwater acoustics, and nanopositioning systems (eg. lithography). Their structural instability plays a key role in their response, with electric fields driving structural distortions that provide large strains. However, this structural instability also causes distortions at the surfaces of the crystals, that have led to structural ambiguity in the literature and contribute to the materials failure mechanisms. Using ID15A, we have applied 1D focused high-energy x-rays to investigate depth dependent surface behaviour in related piezoelectric ceramics. Here, we propose to apply our experience with this method, to the problem of surface structures in relaxor-ferroelectric single crystals. These data are key to building an understanding of the mechanisms of surface phase formation and develop methods for the control of these surface distortions.