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Selected
papers from the latest issue:
Optimal design of a four-sensor probe system to measure the flow properties of the dispersed phase in bubbly air–water multiphase flows
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): S.R. Pradhan , R. Mishra , K. Ubbi , T. Asim
This paper presents a systematic investigation on the design and development of a four-sensor probe system to be used for air–water multiphase flow measurements. A mathematical model is presented which can be used to determine the optimum axial separation of the front sensor with respect to three rear sensors within a four sensor probe system. This system can be used to measure flow properties of the dispersed phase in bubbly air–water flows accurately. Paper also presents a sensitivity analysis to determine the minimum sampling frequency requirements in the data collection process, so that associated errors in various output parameters can be minimized, for the given values of sensors co-ordinates. A particularly novel feature of this paper is development of a unique digital signal processing scheme to enable the accurate computation of different flow characteristics. This paper also presents validation of four-sensor probe measurements from a flow visualization and measurement system which relies on using two high speed cameras mounted orthogonally. The results obtained from validation experiments show very high degree of similarity in measured flow variables from the two systems. This indicates that the four-sensor probe system developed in this study can be used with confidence to measure parameters of a dispersed multiphase flow. The flow characteristics obtained from the four-sensor probe system when used in a multiphase flow system are also presented. The results indicate a unique flow pattern corresponding to bubbles of different sizes in air–water flows.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): S.R. Pradhan , R. Mishra , K. Ubbi , T. Asim
This paper presents a systematic investigation on the design and development of a four-sensor probe system to be used for air–water multiphase flow measurements. A mathematical model is presented which can be used to determine the optimum axial separation of the front sensor with respect to three rear sensors within a four sensor probe system. This system can be used to measure flow properties of the dispersed phase in bubbly air–water flows accurately. Paper also presents a sensitivity analysis to determine the minimum sampling frequency requirements in the data collection process, so that associated errors in various output parameters can be minimized, for the given values of sensors co-ordinates. A particularly novel feature of this paper is development of a unique digital signal processing scheme to enable the accurate computation of different flow characteristics. This paper also presents validation of four-sensor probe measurements from a flow visualization and measurement system which relies on using two high speed cameras mounted orthogonally. The results obtained from validation experiments show very high degree of similarity in measured flow variables from the two systems. This indicates that the four-sensor probe system developed in this study can be used with confidence to measure parameters of a dispersed multiphase flow. The flow characteristics obtained from the four-sensor probe system when used in a multiphase flow system are also presented. The results indicate a unique flow pattern corresponding to bubbles of different sizes in air–water flows.
Non-contact crack detection of high-speed blades based on principal component analysis and Euclidian angles using optical-fiber sensors
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Zhongsheng Chen , Yongmin Yang , Yong Xie , Bin Guo , Zheng Hu
High-speed rotating blades are key mechanical components in turbo-machinery. High cycle fatigues often induce blade cracks and ultimately the loss of blades. Effort has being made to measure on-line blade vibrations and promptly detect potential cracks. Traditional contacting methods are difficult to satisfy the needs of on-line testing, enduring extreme conditions and non-invasion. Nowadays non-contact vibration measurement at blade tips by optical sensing has become a promising approach. In this paper a blade tip-timing (BTT) method using four optical-fiber sensors is presented and all-blade vibration displacements are derived in detail. Blade vibration signals collected by the BTT method are typical sub-sampled signals, so a signal reconstruction method is proposed based on the Shannon sampling theorem. Next nine candidate vibration parameters are calculated to form the crack feature space and principal component analysis (PCA) is used to extract principal components from it. Then Euclidian angles of principal components are defined to detect cracks. In the end, an experimental set-up is built and a small crack is cut on a blade artificially. Collected data are analyzed to testify the proposed method and the experimental results demonstrate its effectiveness.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Zhongsheng Chen , Yongmin Yang , Yong Xie , Bin Guo , Zheng Hu
High-speed rotating blades are key mechanical components in turbo-machinery. High cycle fatigues often induce blade cracks and ultimately the loss of blades. Effort has being made to measure on-line blade vibrations and promptly detect potential cracks. Traditional contacting methods are difficult to satisfy the needs of on-line testing, enduring extreme conditions and non-invasion. Nowadays non-contact vibration measurement at blade tips by optical sensing has become a promising approach. In this paper a blade tip-timing (BTT) method using four optical-fiber sensors is presented and all-blade vibration displacements are derived in detail. Blade vibration signals collected by the BTT method are typical sub-sampled signals, so a signal reconstruction method is proposed based on the Shannon sampling theorem. Next nine candidate vibration parameters are calculated to form the crack feature space and principal component analysis (PCA) is used to extract principal components from it. Then Euclidian angles of principal components are defined to detect cracks. In the end, an experimental set-up is built and a small crack is cut on a blade artificially. Collected data are analyzed to testify the proposed method and the experimental results demonstrate its effectiveness.
Theoretical modeling, simulation and experimental studies of fiber optic bundle displacement sensor
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Supriya S. Patil , P.B. Buchade , A.D. Shaligram
This paper reports unified mathematical model of fiber optic bundle displacement sensor (FOBDS) based on ray tracing technique. The sensor response for concentric, random and hemispherical fiber bundle configurations is simulated using the developed model. The sensor performance parameters viz. sensitivity and linear operating range are calculated by differentiating the sensor response curve. It is observed that for a fiber bundle having two crowns of fibers with central illuminating fiber, sensitivity varies as 0.22, 0.42, 0.47 and linear operating range varies as 40mm, 22mm and 45mm for concentric, random and hemispherical configurations respectively. These results are validated by performing experiments with the developed sensor probe. Experimental results are almost matching the simulated results. After comparing the results for three configurations, it is concluded that the hemispherical configuration is best suitable configuration for sensor showing concurrent improvement in both the sensor performance parameters.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Supriya S. Patil , P.B. Buchade , A.D. Shaligram
This paper reports unified mathematical model of fiber optic bundle displacement sensor (FOBDS) based on ray tracing technique. The sensor response for concentric, random and hemispherical fiber bundle configurations is simulated using the developed model. The sensor performance parameters viz. sensitivity and linear operating range are calculated by differentiating the sensor response curve. It is observed that for a fiber bundle having two crowns of fibers with central illuminating fiber, sensitivity varies as 0.22, 0.42, 0.47 and linear operating range varies as 40mm, 22mm and 45mm for concentric, random and hemispherical configurations respectively. These results are validated by performing experiments with the developed sensor probe. Experimental results are almost matching the simulated results. After comparing the results for three configurations, it is concluded that the hemispherical configuration is best suitable configuration for sensor showing concurrent improvement in both the sensor performance parameters.
Network modeling of multiple-port, multiple-vibration-mode transducers and resonators
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Michael L. Kuntzman , Donghwan Kim , Nishshanka N. Hewa-Kasakarage , Karen D. Kirk , Neal A. Hall
A modeling procedure is presented for multiple-port, multiple-vibration-mode transducers. Unique features of the procedure include the use of modal coordinates to describe deformations of the mechanical structure, the use of a network analog for each vibration mode of the structure, and the selection of modal velocity, rather than a particular physical velocity on the structure, as the mechanical flow variable in each modal network. Finite element analysis is used only to compute a discrete set of salient circuit parameters, with all other analysis and design computations performed using the networks. The approach is computationally efficient and assists with providing insights into the design of actuators and micromechanical resonators, where the generation and suppression of particular vibration modes may be important. A micromachined, multiple-port piezoelectric microphone with in-plane directivity is presented as a case study to demonstrate application of the procedure. Model verification is performed by comparing simulated and measured port-to-port transfer functions over a frequency range spanning several vibration modes of the device. The modeling procedure can address multiple-port sensor response to distributed loadings, selective excitation and suppression of modes in actuator applications, and mixed sensing and actuator applications such as the demonstrated port-to-port measurements.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Michael L. Kuntzman , Donghwan Kim , Nishshanka N. Hewa-Kasakarage , Karen D. Kirk , Neal A. Hall
A modeling procedure is presented for multiple-port, multiple-vibration-mode transducers. Unique features of the procedure include the use of modal coordinates to describe deformations of the mechanical structure, the use of a network analog for each vibration mode of the structure, and the selection of modal velocity, rather than a particular physical velocity on the structure, as the mechanical flow variable in each modal network. Finite element analysis is used only to compute a discrete set of salient circuit parameters, with all other analysis and design computations performed using the networks. The approach is computationally efficient and assists with providing insights into the design of actuators and micromechanical resonators, where the generation and suppression of particular vibration modes may be important. A micromachined, multiple-port piezoelectric microphone with in-plane directivity is presented as a case study to demonstrate application of the procedure. Model verification is performed by comparing simulated and measured port-to-port transfer functions over a frequency range spanning several vibration modes of the device. The modeling procedure can address multiple-port sensor response to distributed loadings, selective excitation and suppression of modes in actuator applications, and mixed sensing and actuator applications such as the demonstrated port-to-port measurements.
SAW-RFID enabled temperature sensor
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Along Kang , Chenrui Zhang , Xiaojun Ji , Tao Han , Ruisheng Li , Xianwei Li
Wireless sensors based on surface acoustic wave (SAW) technology has its own advantages over its counterparts. In this paper, a novel SAW radio frequency identification (RFID) enabled temperature sensor is proposed for industrial applications, in which short measurement range but high accuracy is usually required. The encoding scheme for the sensor using pulse positions combined with phase information is adopted, and then the relationship between the length of a time slot and the decoding errors is deduced to ensure the sensor can be accurately identified, even though ambient temperature fluctuates. In order to solve the phase ambiguity problem involved in temperature measurements more efficiently and reduce the cost of obtaining the unwrapping temperature characteristic curves in the calibration process, an analytical procedure for calculating the variation of phase delay differences with respect to temperature has been proposed. A self-developed burst transceiver supporting online data analysis is also presented. The experimental results demonstrate the effectiveness and practicality of the proposed SAW-RFID enabled temperature sensing scheme, and the prototype sensor within a temperature-controlled oven 2m away from the center of the transceiver antenna in a horizontal orientation achieves an accuracy of ±0.3°C in the temperature range 0–40°C.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Along Kang , Chenrui Zhang , Xiaojun Ji , Tao Han , Ruisheng Li , Xianwei Li
Wireless sensors based on surface acoustic wave (SAW) technology has its own advantages over its counterparts. In this paper, a novel SAW radio frequency identification (RFID) enabled temperature sensor is proposed for industrial applications, in which short measurement range but high accuracy is usually required. The encoding scheme for the sensor using pulse positions combined with phase information is adopted, and then the relationship between the length of a time slot and the decoding errors is deduced to ensure the sensor can be accurately identified, even though ambient temperature fluctuates. In order to solve the phase ambiguity problem involved in temperature measurements more efficiently and reduce the cost of obtaining the unwrapping temperature characteristic curves in the calibration process, an analytical procedure for calculating the variation of phase delay differences with respect to temperature has been proposed. A self-developed burst transceiver supporting online data analysis is also presented. The experimental results demonstrate the effectiveness and practicality of the proposed SAW-RFID enabled temperature sensing scheme, and the prototype sensor within a temperature-controlled oven 2m away from the center of the transceiver antenna in a horizontal orientation achieves an accuracy of ±0.3°C in the temperature range 0–40°C.
Heated atomic force microscope cantilever with high resistivity for improved temperature sensitivity
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Joseph O. Liu , Suhas Somnath , William P. King
We report a heated atomic force microscope cantilever with a heater region engineered to have high temperature sensitivity. The high resistivity (HR) heater region is phosphorous-doped silicon with a doping concentration of 1×1016 cm−3 and a resistivity of 0.53Ω-cm. The heater has a temperature coefficient of resistance of 102ΩC−1 over the temperature range 100–300°C, which is more than one order magnitude higher compared to heated cantilevers from previous publications. When used for thermal sensing of substrate nanotopography, the HR cantilever has a sensitivity of 0.37mV/nm at 300°C. Because the HR cantilever has high sensitivity at relatively low temperatures, it can be used to measure substrates that cannot withstand high temperatures, demonstrated here as a polymer film grating of thickness 110nm.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Joseph O. Liu , Suhas Somnath , William P. King
We report a heated atomic force microscope cantilever with a heater region engineered to have high temperature sensitivity. The high resistivity (HR) heater region is phosphorous-doped silicon with a doping concentration of 1×1016 cm−3 and a resistivity of 0.53Ω-cm. The heater has a temperature coefficient of resistance of 102ΩC−1 over the temperature range 100–300°C, which is more than one order magnitude higher compared to heated cantilevers from previous publications. When used for thermal sensing of substrate nanotopography, the HR cantilever has a sensitivity of 0.37mV/nm at 300°C. Because the HR cantilever has high sensitivity at relatively low temperatures, it can be used to measure substrates that cannot withstand high temperatures, demonstrated here as a polymer film grating of thickness 110nm.
Investigations on non-linear temperature-dependent electro-mechanical response of 1–3 type piezocomposites
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): R. Jayendiran , A. Arockiarajan
An investigation on temperature-dependent behaviour of 1–3 piezocomposites is carried out under electro-mechanical coupled loading condition for different fiber volume fractions and bulk piezoceramics. Effective properties of 1–3 piezocomposite are measured using resonance based method for different operating temperatures. A simple homogenization technique is proposed for predicting the effective properties of 1–3 piezocomposites at elevated temperatures. A thermodynamically consistent uni-axial non-linear constitutive model is developed to predict thermo-electro-mechanical behavior of 1–3 piezocomposites. The predicted effective properties are incorporated in the proposed uni-axial model. The responses of piezocomposites subjected to electric field and mechanical stress are calculated and compared with experimental observations for room and elevated temperatures.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): R. Jayendiran , A. Arockiarajan
An investigation on temperature-dependent behaviour of 1–3 piezocomposites is carried out under electro-mechanical coupled loading condition for different fiber volume fractions and bulk piezoceramics. Effective properties of 1–3 piezocomposite are measured using resonance based method for different operating temperatures. A simple homogenization technique is proposed for predicting the effective properties of 1–3 piezocomposites at elevated temperatures. A thermodynamically consistent uni-axial non-linear constitutive model is developed to predict thermo-electro-mechanical behavior of 1–3 piezocomposites. The predicted effective properties are incorporated in the proposed uni-axial model. The responses of piezocomposites subjected to electric field and mechanical stress are calculated and compared with experimental observations for room and elevated temperatures.
Mechano-electrical conversion for harvesting energy with hybridization of electrostrictive polymers and electrets
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Fouad Belhora , Pierre-Jean Cottinet , Abdelowahed Hajjaji , Daniel Guyomar , M’hammed Mazroui , Laurent Lebrun , Yahia Boughaleb
In recent years, electroactive polymers have been widely used as smart materials. Electromechanical applications are currently focused on energy harvesting, including the development of autonomous device. During the last few years, electrostrictive polymers have been investigated as for energy harvesting. However, for energy scavenging, a static field is necessary, a solution to avoid this problem involves the hybridization of electrostrictive polymers with electrets. The present work has been dedicated to the analytical modeling based on electrostatic and electrostrictive equations. An experimental study was carried out on polyurethane and P(VDF-TrFE-CFE) films, either without filler or filled with carbon nanopowder.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Fouad Belhora , Pierre-Jean Cottinet , Abdelowahed Hajjaji , Daniel Guyomar , M’hammed Mazroui , Laurent Lebrun , Yahia Boughaleb
In recent years, electroactive polymers have been widely used as smart materials. Electromechanical applications are currently focused on energy harvesting, including the development of autonomous device. During the last few years, electrostrictive polymers have been investigated as for energy harvesting. However, for energy scavenging, a static field is necessary, a solution to avoid this problem involves the hybridization of electrostrictive polymers with electrets. The present work has been dedicated to the analytical modeling based on electrostatic and electrostrictive equations. An experimental study was carried out on polyurethane and P(VDF-TrFE-CFE) films, either without filler or filled with carbon nanopowder.
Development of a lead-zirconate-titanate (PZT) thin-film microactuator probe for intracochlear applications
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Chuan Luo , G.Z. Cao , I.Y. Shen
In this paper, we present design, fabrication, and testing results of a small-scale piezoelectric lead-zirconate-titanate (PZT) thin-film microactuator probe that could be implanted in the inner ear for hearing rehabilitation. The PZT probe would generate a pressure wave directly stimulating perilymph in the cochlea to provide acoustic stimulation. Specifically, the PZT probe is 1-mm wide, 10-mm long, and 0.4-mm thick with a PZT thin-film diaphragm at the tip of the probe serving as an acoustic actuator. The diaphragm size is 0.8mm×0.8mm and the probe is packaged with parylene of 0.25-μm thickness. The design effort includes finite element simulations to determine thickness of the parylene package as well as back-of-the-envelope calculations of implantation depth of the PZT probe. The fabrication work includes deposition of a PZT thin film via sol–gel processes, deep reaction ion etching to form an array of vibrating PZT diaphragms, dicing the wafer to release the PZT probes, and application of parylene layer to package the PZT probes. The testing effort includes measurements of actuator velocity (via a laser Doppler vibrometer) and impedance (via an impedance analyzer) in air and in water. After the PZT probe is submerged in water, its displacement gradually increases and saturates at around 2h. Impedance measurements also show a similar trend. To explain these phenomena, we hypothesize that water infiltrates into the PZT thin film via diffusion, thus increasing the dielectric constant of the PZT film. SEM images reveal numerous nano-pores on PZT and probe surfaces, indirectly supporting the hypothesis. The PZT probe functions in water for 55h without breaking down.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Chuan Luo , G.Z. Cao , I.Y. Shen
In this paper, we present design, fabrication, and testing results of a small-scale piezoelectric lead-zirconate-titanate (PZT) thin-film microactuator probe that could be implanted in the inner ear for hearing rehabilitation. The PZT probe would generate a pressure wave directly stimulating perilymph in the cochlea to provide acoustic stimulation. Specifically, the PZT probe is 1-mm wide, 10-mm long, and 0.4-mm thick with a PZT thin-film diaphragm at the tip of the probe serving as an acoustic actuator. The diaphragm size is 0.8mm×0.8mm and the probe is packaged with parylene of 0.25-μm thickness. The design effort includes finite element simulations to determine thickness of the parylene package as well as back-of-the-envelope calculations of implantation depth of the PZT probe. The fabrication work includes deposition of a PZT thin film via sol–gel processes, deep reaction ion etching to form an array of vibrating PZT diaphragms, dicing the wafer to release the PZT probes, and application of parylene layer to package the PZT probes. The testing effort includes measurements of actuator velocity (via a laser Doppler vibrometer) and impedance (via an impedance analyzer) in air and in water. After the PZT probe is submerged in water, its displacement gradually increases and saturates at around 2h. Impedance measurements also show a similar trend. To explain these phenomena, we hypothesize that water infiltrates into the PZT thin film via diffusion, thus increasing the dielectric constant of the PZT film. SEM images reveal numerous nano-pores on PZT and probe surfaces, indirectly supporting the hypothesis. The PZT probe functions in water for 55h without breaking down.
Some practical applications of magnetohydrodynamic pumping
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Champak Das , Guochun Wang , Forrest Payne
Magnetohydrodynamic pumping provides a unique opportunity to mobilize fluids inside a channel using very low power and without employing any external moving parts. In this paper, we illustrate certain unique applications of these pumps such as sample injection, fluid flow in packed bed, and on-chip assay development, all of which are relevant to point-of-care diagnostic device design and fabrication. A linear flow velocity of 5cm/min was obtained using four on-board pumps in a closed loop of circumferential track length of 10cm (channel cross section of 0.5mm×0.5mm), whereas it dropped to 1.8mm/min in a packed bed column operated by a single pump. Finally, these pumps were integrated with silicon immunoassay chips to evaluate the feasibility of transporting electro active species with these pumps from source to electrochemical detection site.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Champak Das , Guochun Wang , Forrest Payne
Magnetohydrodynamic pumping provides a unique opportunity to mobilize fluids inside a channel using very low power and without employing any external moving parts. In this paper, we illustrate certain unique applications of these pumps such as sample injection, fluid flow in packed bed, and on-chip assay development, all of which are relevant to point-of-care diagnostic device design and fabrication. A linear flow velocity of 5cm/min was obtained using four on-board pumps in a closed loop of circumferential track length of 10cm (channel cross section of 0.5mm×0.5mm), whereas it dropped to 1.8mm/min in a packed bed column operated by a single pump. Finally, these pumps were integrated with silicon immunoassay chips to evaluate the feasibility of transporting electro active species with these pumps from source to electrochemical detection site.
Cantilever resonator based on the electrostriction effect in Gd-doped ceria
07 August 2013,
09:38:33
Publication date: 15 October
2013
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Roman Korobko , Ellen Wachtel , Igor Lubomirsky
Thin films of Ce0.8Gd0.2O1.9, which have recently been shown to demonstrate giant electrostriction, are proposed as the active material for miniature cantilever resonators and actuators. In the absence of strain, these films have an electrostriction coefficient within the range of 2–10kPa/(kV/cm)2, as compared with the somewhat larger values for the best commercial electrostrictors (e.g. PbMn 1 / 3 Nb 2 / 3 O 3 , 62kPa/(kV/cm)2. At the same time, Ce0.8Gd0.2O1.9 films can generate stress >70MPa which is competitive with materials currently in use and only limited by the strength of the film-substrate interface. In this report, we investigate two aspects of the practical application of Ce0.8Gd0.2O1.9 as a resonator: the fabrication conditions and the frequency dependence of the electrostrictive behavior. We show that the films can display electromechanical response with frequencies up to 6kHz. With respect to fabrication, we show that Ce0.8Gd0.2O1.9 films have a number of technological advantages when compared to the lead titanate based materials currently in use: (a) they can be deposited on a variety of metal contacts and substrates, including silicon; (b) they do not require high temperature processing; and (c) because Ce0.8Gd0.2O1.9 has cubic symmetry, it can in principle be used as a polycrystalline film with arbitrary texture and does not require poling. In addition, neither Ce nor Gd nor their oxides are toxic; the oxides have very low vapor pressure; and the cations, being highly charged do not diffuse into Si. Consequently, Ce0.8Gd0.2O1.9 films may be readily and advantageously integrated into existing semiconductor fabrication technologies.
Source:Sensors and Actuators A: Physical, Volume 201
Author(s): Roman Korobko , Ellen Wachtel , Igor Lubomirsky
Thin films of Ce0.8Gd0.2O1.9, which have recently been shown to demonstrate giant electrostriction, are proposed as the active material for miniature cantilever resonators and actuators. In the absence of strain, these films have an electrostriction coefficient within the range of 2–10kPa/(kV/cm)2, as compared with the somewhat larger values for the best commercial electrostrictors (e.g. PbMn 1 / 3 Nb 2 / 3 O 3 , 62kPa/(kV/cm)2. At the same time, Ce0.8Gd0.2O1.9 films can generate stress >70MPa which is competitive with materials currently in use and only limited by the strength of the film-substrate interface. In this report, we investigate two aspects of the practical application of Ce0.8Gd0.2O1.9 as a resonator: the fabrication conditions and the frequency dependence of the electrostrictive behavior. We show that the films can display electromechanical response with frequencies up to 6kHz. With respect to fabrication, we show that Ce0.8Gd0.2O1.9 films have a number of technological advantages when compared to the lead titanate based materials currently in use: (a) they can be deposited on a variety of metal contacts and substrates, including silicon; (b) they do not require high temperature processing; and (c) because Ce0.8Gd0.2O1.9 has cubic symmetry, it can in principle be used as a polycrystalline film with arbitrary texture and does not require poling. In addition, neither Ce nor Gd nor their oxides are toxic; the oxides have very low vapor pressure; and the cations, being highly charged do not diffuse into Si. Consequently, Ce0.8Gd0.2O1.9 films may be readily and advantageously integrated into existing semiconductor fabrication technologies.
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