Details of Grant 

EPSRC Reference:	GR/A10550/01
Title:	AF: MICROMECHANICAL DESIGN OF FERROELECTRIC DEVICES
Principal Investigator:	Huber, Dr JE
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Department:	Engineering
Organisation:	University of Cambridge
Scheme:	Advanced Fellowship (Pre-FEC)
Starts:	01 October 2001	Ends:	30 September 2006	Value (£):	206,508
EPSRC Research Topic Classifications:	Electromagnetics Electronic Devices & Subsys.
EPSRC Industrial Sector Classifications:	No relevance to Underpinning Sectors
Related Grants:
Panel History:
Summary on Grant Application Form
Ferroelectric materials used in sensors and actuators are performance limited by failure initiated from incipier flaws, electrodes and points of surface indentation. The understanding of indentation and cracking problems u ferroelectrics is hindered by insufficient knowledge of the micromechanics of the failure processes. This research aims t establish by experiment answers to the fundamental questions about cracks and other field intensifiers in ferroelectrics Regarding cracks: are they permeable or impermeable? conductive or insulating? Does crack closure produce wedgirn contact at crack surface asperities? What mechanisms control crack growth under cyclic loading? Regarding electrode and indentations: what are the associated field intensities? How do they initiate cracks? What design measures ca alleviate their effects? Birefringent ferroelectrics will be used to measure field intensities at cracks, indentations an electrode edges. The results will be compared with predictions using a recent constitutive model. Design rules will b developed for predicting the performance actuators and sensors and improved device designs will be explored.An application of ferroelectrics is in transducers using the transition to an antiferroelectric phase. Here, there i a need for a constitutive description accounting for both ferroelectric switching and the phase transition. A multi-axis ferroelectrics model (developed by Fleck and Huber) will be used to describe this phase transition. Modelling work will b supported by measurements of the transducer material response under combined electro-mechanical loading
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Organisation Website:	http://www.cam.ac.uk