CPM8.1 task 6. Evaluation of new functional materials

A PMN-PT relaxor electrostrictive and a single crystal PZN-4.5%PT have been evaluated using a range of high and low field piezoelectric characterisation techniques. The performance of electrostrictives under high AC fields gives similar output to a soft PZT. The single crystal exhibited piezoelectric activity 2-3 times that of a soft PZT composition, and the maximum achievable strain was almost an order of magnitude greater. A 95/5 PZT material exhibited a field induced phase transition from antiferroelectric to ferroelectric at around 3.5kV/mm and is associated with a strain of around 0.16%. The fields needed to achieve this strain are close to the breakdown strength of the material of around 8kV/mm. (author)