Fixing of volume holograms in ferroelectric K(1-y)Li(y)Ta(1-x)Nb(x)O(3)

We report on the fixing of photorefractive volume holograms in potassium lithium tantalate niobate with ionic gratings and also with ferroelectric domain-reversed gratings. A diffraction efficiency of 55% is obtained with domain reversal in a 2-mm-thick ferroelectric phase K(1-y)Li(y)Ta(1-x)Nb(x)O(3) crystal doped with Co, V, and Ti. We measured the decay rate of the domain gratings and also of the initial electron gratings and ion gratings. The domain grating decay agrees with Vogel-Fulcher fits. The activation energies for ionic and electronic conductivity are 0.76 and 0.12 eV, respectively.