The low-field electrical behavior of relaxor ferroelectric ceramics has been qualitatively described by many parameters, including diffuseness (6), which characterizes the breadth of the transition peak and is roughly related to the standard deviation of the peak. Three major types of equations have been used to calculate 6: Gaussian distribution (originated by Smolenskii and Rolov et d.), power law (used by many authors), and variable power law (Uchino et al). In this work, the three calculational techniques are compared analytically and illustrated using dielectric data from ceramic 0.88Pb(Mg1,3Nbzi3)03. 0.12PbTi03. All three methods of analysis result in very linear plots; however, the calculated values of S are significantly different. A method of limitingthe temperature range to that corresponding to 2/3 of the maximum relative dielectric constant is suggested in order to decrease the deviations. This limitation is shown to give consistent reproducible diffuseness values without extraneous contributions arising from the relaxor nature of the material or from differing temperature ranges of measurement, thus allowing 6 to be used as an effective comparative parameter for relaxor ceramics. [

electrostrictive actuators are large capacitors with the added complexity of having to perform mechanically as well as electrically. High operating fields and severe operating conditions make it necessary to predict and liimit stress levels generated in the device. A constitutive three-dimensional model for electrostrictors has been develoiped and implemented as a design tool for actuators. The effects of electrode geometry and transition-layer thickness on stress levels have been modeled and failure in high-stress regioins has been correlated with the presence of flaws (pores andl delaminations) in the devices. [

The tetragonal tungsten bronze (TTB) type of Sr,Bal-,-Nb206 (SBN) (0.5 5 x 5 0.75) was synthesized by a mixedoxide route. Using the two-step densification process of pressureless sintering followed by oxygen HIPing, transparent ceramics were successfully fabricated. Microstructural, dielectric, optical, and electrooptic properties were investigated. All single-phase TTB-type SBN showed the characteristics of relaxor ferroelectrics. The extinction coefficients of the sample with the highest transparency were calculated from transmission spectra to be 30.4, 5.8, and 2.4 cm-I at 600, 1450, and 2000 nm, respectively. The linear electrooptic coefficients for SBN55, r33 and rI3, were 46 X lo-'' and 21 X lo-'' m/V at 633 nm, respectively. [

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