Measurement system for electric field-induced strain by use of displacement magnification technique

A new, simple, and precise method has been developed for the measurement of electric field-induced strain, which is based on the displacement magnification technique, This technique is stable against environmental vibration noises, and is able to measure strains with 6 to 10 times higher resolution than that of a displacement sensor itself. Using this method, I constructed a novel measurement system which simultaneously collects data of field-induced strain: strain rate, polarization, current and acoustic emission (AE) under high electric field drive for piezoelectric and electrostrictive materials, The system reveals, for soft tetragonal lead zirconate titanate (PZT) ceramics, that 180 deg domain walls move before 90 deg domain walls move at around the coercive electric field strength under +/- 1500 V/mm electric field drive at a frequency of 0.05 Hz. AE is not generated around the coercive electric field, but is at high strain state. Some discussions are given about the origins of these phenomena.