A study of dkdp and kdp crystals in an applied electric field by synchrotron radiation topography

Abstract

Crystals of DKDP and KDP were examined by synchrotron radiation topography with in situ variation of temperature and applied electric field. Both the phase transition structure and the electric domain structure were imaged, and use of a television image converter permitted dynamic observations to be made. A lamellar phase transition was observed in DKDP but not in KDP, possibly because of the lower temperature hysteresis in the latter. Repolarisation under electric field involves the smooth motion of packets of domains with continuous change of the disorientation angle. Domain-packet motion begins at a field of modulus 0.1-0.2 kV cm-1 and is complete at 1 kV cm-1.