The nature of large dielectric constant of relaxors

Relaxors are used as non-hysteresis (electrostrictive) actuator materials applied in micromechanics and as microdrivers for microwave mechanically tunable filters and phase shifters. Displacement produced by the actuator is determined by the value of relaxor dielectric permittivity (ε). To estimate the limitations in the operation speed of relaxor-based electronic devices, the frequency dispersion of relaxor ε is studied in wide frequency range. It is assumed that dominating contribution to the relaxor material ε is electromechanical coupling of polar clusters. So the response speed of relaxor-based devices is determined by the sound speed in the relaxor material.