Journal of Electroceramics 

About: Journal of Electroceramics is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Dielectric & Ceramic. It has an ISSN identifier of 1385-3449. Over the lifetime, 2098 publications have been published receiving 49678 citations.

Conduction Model of Metal Oxide Gas Sensors

Abstract: Tin dioxide is a widely used sensitive material for gas sensors. Many research and development groups in academia and industry are contributing to the increase of (basic) knowledge/(applied) know-how. However, from a systematic point of view the knowledge gaining process seems not to be coherent. One reason is the lack of a general applicable model which combines the basic principles with measurable sensor parameters. The approach in the presented work is to provide a frame model that deals with all contributions involved in conduction within a real world sensor. For doing so, one starts with identifying the different building blocks of a sensor. Afterwards their main inputs are analyzed in combination with the gas reaction involved in sensing. At the end, the contributions are summarized together with their interactions. The work presented here is one step towards a general applicable model for real world gas sensors.

Lead-free piezoelectric ceramics: Alternatives for PZT?

Abstract: Investigations in the development of lead-free piezoelectric ceramics have recently claimed comparable properties to the lead-based ferroelectric perovskites, represented by Pb(Zr,Ti)O3, or PZT In this work, the scientific and technical impact of these materials is contrasted with the various families of “soft” and “hard” PZTs On the scientific front, the intrinsic nature of the dielectric and piezoelectric properties are presented in relation to their respective Curie temperatures (T C) and the existence of a morphotropic phase boundary (MPB) Analogous to PZT, enhanced properties are noted for MPB compositions in the (Na,Bi)TiO3-BaTiO3 and ternary system with (K,Bi)TiO3, but offer properties significantly lower The consequences of a ferroelectric to antiferroelectric transition well below T C further limits their usefulness Though comparable with respect to T C, the high levels of piezoelectricity reported in the (K,Na)NbO3 family are the result of enhanced polarizability associated with the orthorhombic-tetragonal polymorphic phase transition being compositionally shifted downward As expected, the properties are strongly temperature dependent, while degradation occurs through the thermal cycling between the two distinct ferroelectric domain states Extrinsic contributions arising from domains and domain wall mobility were determined using high field strain and polarization measurements The concept of “soft” and “hard” lead-free piezoelectrics were discussed in relation to donor and acceptor modified PZTs, respectively Technologically, the lead-free materials are discussed in relation to general applications, including sensors, actuators and ultrasound transducers

Ferroelectric materials for microwave tunable applications

Abstract: A review of the properties of ferroelectric materials that are relevant to microwave tunable devices is presented: we discuss the theory of dielectric response of tunable bulk materials and thin films; the experimental results from the literature and from own work are reviewed; the correspondence between the theoretical results and the measured properties of tunable materials is critically analyzed; nominally pure, real (defected), and composite bulk materials and thin films are addressed. In addition, techniques for characterization of tunable ferroelectrics and applications of these materials are briefly presented.

Thin Film Piezoelectrics for MEMS

Abstract: Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements This paper reviews the literature in this field, with an emphasis on the factors that impact the magnitude of the available piezoelectric response For non-ferroelectric piezoelectrics such as ZnO and AlN, the importance of film orientation is discussed The high available electrical resistivity in AlN, its compatibility with CMOS processing, and its high frequency constant make it especially attractive in resonator applications The higher piezoelectric response available in ferroelectric films enables lower voltage operation of actuators, as well as high sensitivity sensors Among ferroelectric films, the majority of the MEMS sensors and actuators developed have utilized lead zirconate titanate (PZT) films as the transducer Randomly oriented PZT films show piezoelectric e(31, f) coefficients of about - 7 C/m(2) at the morphotropic phase boundary In PZT films, orientation, composition, grain size, defect chemistry, and mechanical boundary conditions all impact the observed piezoelectric coefficients The highest achievable piezoelectric responses can be observed in {001} oriented rhombohedrally-distorted perovskites For a variety of such films, e(31,f) coefficients of - 12 to - 27 C/m(2) have been reported

Advances in energy harvesting using low profile piezoelectric transducers

Abstract: The vast reduction in the size and power consumption of sensors and CMOS circuitry has led to a focused research effort on the on-board power sources which can replace the batteries. The concern with batteries has been that they must always be charged before use. Similarly, the sensors and data acquisition components in distributed networks require centralized energy sources for their operation. In some applications such as sensors for structural health monitoring in remote locations, geographically inaccessible temperature or humidity sensors, the battery charging or replacement operations can be tedious and expensive. Logically, the emphasis in such cases has been on developing the on-site generators that can transform any available form of energy at the location into electrical energy. Piezoelectric energy harvesting has emerged as one of the prime methods for transforming mechanical energy into electric energy. This review article provides a comprehensive coverage of the recent developments in the area of piezoelectric energy harvesting using low profile transducers and provides the results for various energy harvesting prototype devices. A brief discussion is also presented on the selection of the piezoelectric materials for on and off resonance applications. Analytical models reported in literature to describe the efficiency and power magnitude of the energy harvesting process are analyzed.