IEEE Symposium on Ultrasonics · 2002 · 24 citations · 18 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsCeramicsUltrasoundFerroelectric CeramicsFerroelectric MaterialsPiezoelectric CeramicsPiezoelectric MaterialsTransducer TechnologyUltrasonicsDielectric ConstantElectromechanical CouplingPiezoelectric PropertiesPiezoelectric TransducersPiezoelectricityRelaxor FerroelectricsTransducer MaterialsUltrasonic Transducers
Novel ultrasonic transducers whose sensitivity can be controlled with a DC bias field have been developed by utilizing relaxor ferroelectrics as a transducer material in place of conventional piezoelectrics. Relaxor ferroelectrics have a large bias-field-induced piezoelectricity as well as a giant electrostrictive effect due to their extremely large dielectric constant ( approximately 10/sup 4/). Pb(Mg/sub 1/3/Nb/sub 2/3/)O/sub 3/ (PMN) is a typical relaxor ferroelectric having a diffuse phase transition at around 0 degrees C. The addition of 9 mol.% of PbTiO/sub 3/ to the PMN is found to produce a transducer material whose electromechanical coupling factor for the thickness mode is comparable to that of PZT ceramics for a practical DC bias field. It is suggested that the application of recent piezoceramic/polymer composite technology to this relaxor ferroelectric transducer can play an important role in developing two-dimensional arrays.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
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