DEVELOPMENT OF HIGH-STRAIN LOW-HYSTERESIS ACTUATORS USING ELECTROSTRICTIVE LEAD MAGNESIUM NIOBATE (PMN)

This paper describes the development of high-strain, low-hysteresis actuators using the lead magnesium niobate composition 0.9PMN-0.1PT. The material was fabricated using an economical direct synthesis technique, similar to that used for conventional PZT ceramics. In 0.9PMN-0.1PT a large electrostrictive effect occurs near the broad maxima of the dielectric permittivity. The samples reported here exhibited a strain of over 0.12% at a field of 3.5 MV/m and the maximum dielectric constant at 38 o C and 100 Hz was over 30,000. The maximum field-dependent d 33 occurred near 0.4 MV/m and had a value of 1776 pC/N. The PMN material is suitable for smart structure applications that require precision actuation with low hysteresis. PMN samples have been fabricated in a variety of configurations including disks, plates, tubes and multi-layer stacks. This paper presents electrical, piezoelectric and mechanical data for single-layer samples and for a multi-layer stack.