Importance of structural irregularity on dielectric loss in (1-x)Pb(Mg1/3Nb2/3)O-3-(x)PbTiO3 crystals

The dielectric properties of (1-x)Pb(Mg1/3Nb2/3)O-3-(x)PbTiO3 (PMN-PT) crystals have been investigated over a temperature range of 4 to 450 K at various frequencies. At low temperatures, an unusual frequency dependent plateau region in the absorption was observed between 75 and 175 K. At both higher and lower temperatures, the absorption was frequency independent. Analysis of the relaxation time constant revealed power-law divergence, typical of fractal behavior in disordered magnetic systems. The results demonstrate the importance of structural irregularities on the dielectric loss mechanism in poled oriented PMN-PT crystals. (C) 2002 American Institute of Physics.