Polar tweed was discovered in mechanically stressed LaAlO3. Local patches of strained material (diameter ca. 5 μm) form interwoven patterns seen in birefringence images, Piezo-Force Microscopy (PFM) and Resonant Piezoelectric Spectroscopy (RPS). PFM and RPS observations prove unequivocally that electrical polarity exists inside the tweed patterns of LaAlO3. The local piezoelectric effect varies...

Ferroelectric materials, which exhibit switchable polarization and are piezoelectric, have been extensively studied because of their applications in nonvolatile memory and energy harvesting devices.[1,2] Recently, ferroelectric nanostructures have attracted great interest as they provide a platform to investigate the size effect of ferroelectricity and enable integration with prevailing miniatu...

A new piezoelectric-based mechanism was proposed, modeled and tested. This mechanism was basically designed to be periodically excited while in contact with a driven surface. Two piezoelectric elements located by the angle of 901 relative to each other are used to create elliptical motion on tip of the mechanism depending on the applied phase difference. In order to ensure the designated ellipt...

Piezoelectric dynamometers are out of use in high humidity. Experimental results showed that piezoelectric coefficients measured by the force-induced charges method initially fluctuated in a small range and then was unstable, and they could not be measured at high relative humidity (RH). The traditional shielding method-insulation paste was not quiet convenient, and it even added the weight of ...

In this paper, the vibration characteristics of multi-layer shell that internal and external surfaces with a layer of piezoelectric sensor and actuator is investigated. The backrest shell laminated with simple analytical method to evaluate and the results were compared with results obtained by other researchers. The numerical solution methods (GDQ) for shells with piezoelectric layers and plain...

We have calculated the piezoelectric field and charge distribution for various III-nitride heterostructures. Our calculations include strain energy minimization and doping effects, and are presented to show the magnitude of piezoelectric effects in strained layers. We compare our calculated results to device results where available. These include the two-dimensional electron gas in heterojuncti...

P iezoelectric materials are the key functional component in many devices, such as sensors, actuators, ultrasonic transducers, sonar systems, and energy scavengers. These applications take advantage of the direct or reverse piezoelectric effects caused by simultaneous shifts in positive and negative charge centers within the primitive unit cell in response to mechanical deformation. Ideal piezo...

In this research, a functionally graded microbeam bonded with piezoelectric layers is analyzed under electric force. Static and dynamic instability due to the electric actuation is studied because of its importance in micro electro mechanical systems, especially in micro switches. In order to prevent pull-in instability, two piezoelectric layers are used as sensor and actuator. A current amplif...