We have developed a uniform and dense epitaxial thinfilm of 0.94(Bi_(0.5)Na_(0.5))TiO_(3)-0.04×(Bi_(0.5)Na_(0.5))TiO_(3)-0.02BaTiO_(3)on a SrRuO_(3)coated SrTiO_(3)substrate by pulsed laser deposition method.The ...We have developed a uniform and dense epitaxial thinfilm of 0.94(Bi_(0.5)Na_(0.5))TiO_(3)-0.04×(Bi_(0.5)Na_(0.5))TiO_(3)-0.02BaTiO_(3)on a SrRuO_(3)coated SrTiO_(3)substrate by pulsed laser deposition method.The remnant polarization,coercivefield and dielectric constant of thefilm with thickness of 315 nm,were measured to be 16.6μC·cm^(-2),147.5 kV·cm^(-1)and 640(at 1 kHz),respectively.Thefilm exhibited a high breakdown voltage and low leakage current of 1.1×10^(-5)A·cm^(-2)at 310 kV·cm^(-1).This(Bi_(0.5)Na_(0.5))TiO_(3)-based thinfilm with a target composition in the rhombohedral side of the morphotropic phase boundary can be considered a potential candidate for relatively high power applications.展开更多
Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging.In this paper,firstly,the most promising lead-free compositions with perovskite structure for medical imaging applications ha...Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging.In this paper,firstly,the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed.The electromechanical properties of various lead-free ceramics,composites,and single crystals based on barium titanate,bismuth sodium titanate,potassium sodium niobate,and lithium niobate are presented.Then,fundamental principles and design considerations of ultrasonic transducers are briefly described.Finally,recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers.Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained.Additionally,acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging,in vitro intravascular ultrasound imaging of swine aorta,and in vivo or ex vivo imaging of human eyes and skin are reviewed.展开更多
基金The-nancial support of this work by the Glenn Howatt foundation is sincerely appreciated by the authors.
文摘We have developed a uniform and dense epitaxial thinfilm of 0.94(Bi_(0.5)Na_(0.5))TiO_(3)-0.04×(Bi_(0.5)Na_(0.5))TiO_(3)-0.02BaTiO_(3)on a SrRuO_(3)coated SrTiO_(3)substrate by pulsed laser deposition method.The remnant polarization,coercivefield and dielectric constant of thefilm with thickness of 315 nm,were measured to be 16.6μC·cm^(-2),147.5 kV·cm^(-1)and 640(at 1 kHz),respectively.Thefilm exhibited a high breakdown voltage and low leakage current of 1.1×10^(-5)A·cm^(-2)at 310 kV·cm^(-1).This(Bi_(0.5)Na_(0.5))TiO_(3)-based thinfilm with a target composition in the rhombohedral side of the morphotropic phase boundary can be considered a potential candidate for relatively high power applications.
文摘Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging.In this paper,firstly,the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed.The electromechanical properties of various lead-free ceramics,composites,and single crystals based on barium titanate,bismuth sodium titanate,potassium sodium niobate,and lithium niobate are presented.Then,fundamental principles and design considerations of ultrasonic transducers are briefly described.Finally,recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers.Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained.Additionally,acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging,in vitro intravascular ultrasound imaging of swine aorta,and in vivo or ex vivo imaging of human eyes and skin are reviewed.
