Investigation of glassy behavior in lead barium ytterbium tantalate relaxors

The glassy behavior of lead barium ytterbium tantalate relaxors has been investigated. The frequency dependence of the temperature, T′_m (the temperature corresponding to the maximum value dielectric constant) is analyzed using Vogel-Fulcher relation and power law. The fitting parameters reveal that the power law explains the relaxation mechanism much better than the Vogel-Fulcher relation. The temperature dependence of dielectric constant at temperatures much higher and lower than T′_m is analyzed by two exponential functions, which gives an idea about the production of polar clusters at high temperature and the distribution of freezing temperatures at lower temperature.