On the dynamics of periodically-poled lithium niobate formation by off-center Czochralski technique

The formation mechanisms which might be responsible for the domain structur es observed in periodic-poled lithium niobate crystals grown by the off-cen ter Czochralski technique were investigated varying the process parameters. We show that the periodic inverted domains structure does not maintain the polarization over the whole crystal, as commonly accepted. In particular, a "separation plane" parallel to the growth axis exists and divides the cry stal in two halves, each with periodic structure but with opposite domain s equences. A possible explanation of the phenomenon is presented invoking bo th the thermoelectric effect and its correlation to the dynamic temperature fluctuation experienced by the growing crystal. (C) 2001 American Institut e of Physics.