Effects of thermal treatment and dc bias on dielectric aging in the plzt 9.5:65:35 relaxor ferroelectric ceramic

Abstract

The dielectric aging effects after thermal treatments and under DC bias were studied and delineated for Lead Lanthanum Zirconate Titanate (PLZT 9.5:65:35) relaxor ceramic. Under room temperature aging, dielectric constant and loss tangent as a function of aging time obey a power law (K = Kot “) and the power index (n) follows the logarithmic law with measured frequency. The aging rate was enhanced by the quenching prior to the aging process. The DC bias reduced the aging rate especially under high measured frequencies. During aging, the Cole-Cole plot shrinks with aging time in such a way that the average relaxation time constant decreases and the distribution of relaxation time constant become narrow with aging time. All the effects are correlated and modeled with the characteristics of relaxor ferroelectrics. The aging process looks like that the polar microregions have a preferred orientation corresponding to the deepest minimum in energy and its contribution to the total permittivity will decrease.