A ceramic fuel cell in an all solid-state energy conversion device that produces electricity by electrochemically combining fuel and oxidant gases across an ionic conducting oxide. Current ceramic fuel cells use an oxygen-ion conductor or a proton conductor as the electrolyte and operate at high temperatures (>600°C). Ceramic fuel cells, commonly referred to as solid-oxide fuel cells (SOFCs), are presently under development for a variety of power generation applications. This paper reviews the science and technology of ceramic fuel cells and discusses the critical issues posed by the development of this type of fuel cell. The emphasis is given to the discussion of component materials (especially, ZrO2 electrolyte, nickel/ZrO2 cermet anode, LaMnO3 cathode, and LaCrO3 interconnect), gas reactions at the electrodes, stack designs, and processing techniques used in the fabrication of required ceramic structures.

Ceramic Fuel Cells

Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics are reviewed with the aim of providing an insight into different processes which may affect the behaviour of ferroelectric devices, such as ferroelectric memories and micro-electro-mechanical systems. Taking into consideration recent advances in this field, topics such as polarization switching, polarization fatigue, effects of defects, depletion layers, and depolarization fields on hysteresis loop behaviour, and contributions of domain-wall displacement to dielectric and piezoelectric properties are discussed. An introduction into dielectric, pyroelectric, piezoelectric and elastic properties of ferroelectric materials, symmetry considerations, coupling of electro-mechanical and thermal properties, and definitions of relevant ferroelectric phenomena are provided.

https://iopscience.iop.org/article/10.1088/0034-4885/61/9/002/pdf

Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics

An overview of the state of art in ferroelectric thin films is presented. First, we review applications: microsystems' applications, applications in high frequency electronics, and memories based on ferroelectric materials. The second section deals with materials, structure (domains, in particular), and size effects. Properties of thin films that are important for applications are then addressed: polarization reversal and properties related to the reliability of ferroelectric memories, piezoelectric nonlinearity of ferroelectric films which is relevant to microsystems' applications, and permittivity and loss in ferroelectric films-important in all applications and essential in high frequency devices. In the context of properties we also discuss nanoscale probing of ferroelectrics. Finally, we comment on two important emerging topics: multiferroic materials and ferroelectric one-dimensional nanostructures. (c) 2006 American Institute of Physics.

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Ferroelectric thin films: Review of materials, properties, and applications

Progress in material selection for solid oxide fuel cell technology: A review

Small, light weight and multifunctional electronic components are attracting much attention because of the rapid growth of the wireless communication systems and microwave products in the consumer electronic market. The component manufacturers are thus forced to search for new advanced integration, packaging and interconnection technologies. One solution is the low temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional ceramic modules with low dielectric loss and embedded silver electrodes. During the past 15 years, a large number of new dielectric LTCCs for high frequency applications have been developed. About 1000 papers were published and ∼500 patents were filed in the area of LTCC and related technologies. However, the data of these several very useful materials are scattered. The main purpose of this review is to bring the data and science of these materials together, which will be of immense help to researchers and technologists all over the world. The comme...

Low loss dielectric materials for LTCC applications: a review

Epitaxial, c‐oriented YBa2Cu3Ox thin films were deposited by dc sputtering on (1102)‐sapphire substrates with an intermediate buffer layer of Y‐stabilized ZrO2 (YSZ), which was grown by rf magnetron sputtering. The epitaxy of the YSZ and the YBa2Cu3Ox films was proved by Rutherford backscattering spectrometry combined with ion channeling. The YBa2Cu3Ox films exhibited transition temperatures of 90 K and had critical current densities exceeding 1.2×106 A/cm2 at 77 K in zero magnetic field.

Epitaxial YBa2Cu3Ox thin films on sapphire using a Y‐stabilized ZrO2 buffer layer

A device for detecting at least one substance of a fluid includes at least one piezo-acoustic resonator with at least one piezo layer, an electrode arranged on the piezo-electric layer, at least one other electrode arranged on the piezo-electric layer and a surface section used for sorption of the substance of the fluid. The piezo-electric layer, the electrodes and the surface section are disposed in such a way that electric control of the electrodes leads to an oscillation of the resonator at a resonance frequency which depends upon the amount of the substance which is sorbed on the surface section. The thickness of the pioelectric layer is in the region of 0.5 to 20 μm and the resonance frequency of the oscillation ranges from 500 MHz to 2 GHz. The device is a mass sensor with a piezo-acoustic high-frequency thin film resonator.

Device and method for detecting a substance of a liquid

The postresonator method proposed by Hakki and Coleman for the measurement of dielectric properties of solids in the microwave region is reexamined. Based on the experiments performed around 10 GHz, the limitations of the method in loss determination for materials with tan delta < 5 x 10(-4) are outlined. Alternative techniques for studying high-Q materials are described. Loss measurements performed on well-prepared ceramics have been used to draw comparisons among these techniques. Some of the experimental findings are new and are reported for the first time.

Dielectric measurements on high-Q ceramics in the microwave region

The hysteresis characteristics of stabilized Pb(Ti, Zr)3 ceramics are normally described by the introduction of an internal bias field. It is shown that the domain reversals are controlled by this field but that this field does not really exist inside the ceramic grains. A stabilization model describing the field distribution within a ceramic sample during switching will be presented.

On the stabilizing field of lead-titanate-zirconate ceramics doped with transition metal ions

After a short description of thermal conditions in a pyroelectric sensor, substantial requirements to pyroelectric thin film and sensor design are derived from the theoretical basics. A planar multi-target sputtering process is used to deposit PZT thin films for application in pyroelectric IR sensors. The self-polarized PZT are characterized by a pyroelectric coefficient p of 2-10−4 Cm−2K−1, a dielectric constant [Sgrave] of 300 and a dielectric loss tan δ of 0.01. These material properties, including a low tensile stress of the sensor layer stack of + 110 Mpa, as well as standard microelectronic technologies make the films suitable for the use in pyroelectric sensor arrays. Fabricated singleelement sensors have a specific detectivity D* (500K, 10 Hz) of 3.108 cmHz1/2W−1. An 11×6 array sensor has been developed for motion detection. The array pixels with a sensitive area of 0.0784 mm2 have a noise equivalent power NEP of less than 0.7 nW at 1 Hz.

Wolfram Wersing

Papers

Epitaxial YBa2Cu3Ox thin films on sapphire using a Y‐stabilized ZrO2 buffer layer

Device and method for detecting a substance of a liquid

Dielectric measurements on high-Q ceramics in the microwave region

On the stabilizing field of lead-titanate-zirconate ceramics doped with transition metal ions

Pyroelectric devices based on sputtered PZT thin films