For epitaxial films, a critical thickness (tc) can create a phenomenological interface between a strained bottom layer and a relaxed top layer. Here, we present an experimental report of how the tc in BiFeO3 thin films acts as a boundary to determine the crystalline phase, ferroelectricity, and piezoelectricity in 60 nm thick BiFeO3/SrRuO3/SrTiO3 substrate. We found larger Fe cation displacemen...

The proportional and derivative nonlinear potential feedback controls via piezoelectric sensor and actuator layers are used. A simple and consistent model combining the geometrical nonlinear affects and the feedback control of a piezoelectric/elastic/piezoelectric sandwich beams is derived. A mathematical methodology based on the multiple scales method for nonlinear vibration control of seconda...

Theoretical calculations have been performed to study the effects of piezoelectric fields in superlattice systems. The results show that cubic strained superlattices and quantum wells subjected to variable temperature and pressure exhibit changes in their piezoelectric fields. We consider superlattice systems grown in arbitrary directions, with a thickness smaller and larger than the critical t...

The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, acti...

This thesis is concerned with an investigation of the control of responses of plate structures with piezoelectric layers and under complicated excitations modeled as a non-stationary random process. The plate structures and piezoelectric layers are both discretized by the mixed formulation finite element method (FEM). The investigation consists of three parts. The first part is a literature sur...

Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor ...

The remnant polarization of weakly coupled ferroelectric-dielectric superlattices is distributed unequally between the component layers, and as a result the components respond differently to applied electric fields. The difference is apparent in both the nanometer-scale structure of striped polarization domains and in the development of piezoelectric strain and field-induced polarization. Both ...

ACKNOWLEDGEMENT It gives me immense pleasure to express my deep sense of gratitude to my supervisor Prof. Tarapada Roy and Prof. Haraprasad Roy for their invaluable guidance, motivation, constant inspiration and above all their ever cooperating attitude enabled me in bringing up this thesis in present elegant form.