Abstract

KLTN is a new photorefractive material that is very promising for all-optical switching applications. Its composition can be tuned to present a ferroelectric transition at room temperature while keeping its high crystalline quality. The structure of KLTN was determined by neutron diffraction. Measurements taken above and below the ferroelectric transition demonstrate the change of symmetry and the ionic displacements. The Nb ion performs the most substantial shift. The data analysis indicates that the structural transition is not a pure displacive one but contains at least some fraction of an order/disorder transition. The nature of the transition and its relation to disorder at the Nb/Ta site will be discussed.

© 2001 Optical Society of America