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W. G. Pritchard Lab Seminar: 11:15 AM - 12:15 PM, 216 McAllister Bldg

	            **Monday October 31, 2005**
	
Domain dependence of piezoelectricity in domain-engineered crystals

Wenwu Cao

Department of Mathematics
Penn State University

Abstract:

Experimental studies indicate that the effective properties of multi-
domain ferroelectric crystals strongly depend on the domain size. Using a 
2-D time-dependent Landau-Ginzburg model incorporating elastic, 
electrostatic and electromechanical interactions, we have simulated the 
piezoelectric properties of domain engineered ferroelectric single 
crystals. Three different microstructures with different sized domains are 
analyzed. We have found that the field-induced phase transitions are 
highly sensitive to the direction of the field relative to the crystal 
axes, and to the domain size. Since the proximity to the transition 
enhances piezoelectric behavior, the effective piezoelectric constants of 
smaller domain is significantly enhanced. Our model may also explain 
domain size dependence in other single crystal systems.

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