A large body of work has been reported in the last 5 years on the development of lead-free piezoceramics in the quest to replace lead–zirconate–titanate (PZT) as the main material for electromechanical devices such as actuators, sensors, and transducers. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented. Suitable chemical elements are selected first on the basis of cost and toxicity as well as ionic polarizability. Different crystal structures with these elements are then considered based on simple concepts, and a variety of phase diagrams are described with attractive morphotropic phase boundaries, yielding good piezoelectric properties. Finally, lessons from density functional theory are reviewed and used to adjust our understanding based on the simpler concepts. Equipped with these guidelines ranging from atom to phase diagram, the current development stage in lead-free piezoceramics is then critically assessed.

Perspective on the Development of Lead-free Piezoceramics

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

Luminescence and scintillation characteristics of four selected material systems, namely CsI:Tl(Na), CeF 3 , PbWO 4 and Ce-doped aluminium perovskites XAIO 3 :Ce (X=Y, Lu, Y-Lu) are reviewed. The progress in their physical understanding and related optimisation of their characteristics and technology are demonstrated. The important role of various defect states in the scintillator performance of these materials is stressed, which has led to the need for a deeper study of the processes of energy transfer and storage to achieve their intrinsic limits and full exploitation in scintillation detectors.

Wide Band Gap Scintillation Materials: Progress in the Technology and Material Understanding

This article focuses on n-type doped transparent conducting binary oxides – namely, those with the general formula MxOy:D, where MxOy is the host oxide material and D is the dopant element. Such materials are of great industrial importance in modern materials chemistry. In particular, there is a focus on the search for alternatives to indium-based materials, prompted by indium's problematic supply risk as well as a number of functional factors. The important relationship between computational study and experimental observation is explored, and an extensive comparison is made between the electrical properties of a number of the most interesting experimentally-prepared materials. In writing this article, we aim to provide both an accessible tutorial of the physical descriptions of transparent conducting oxides, and an up-to-date overview of the field, with a brief history, some key accomplishments from the past few decades, the current state of the field as well as postulation on some likely future developments.

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n-Type doped transparent conducting binary oxides: an overview

We report several wet-chemical methods for synthesis of one-dimensional CuO nanostructures in water−ethanol mixed solvents at 77−82 °C and 1 atm. Single-crystalline monodispersed CuO nanorods with a selected breadth in the range of 5−15 nm have been prepared by controlling reagent concentrations. The nanorods are preferentially grown along 〈010〉 directions. A two-step continuous process has also been developed to prepare CuO nanorods and ribbons (length up to 1 μm) with a large aspect ratio under pseudo-steady-state operation. Furthermore, a two-dimensional netted structure has been assembled for the first time from short nanorods formed after prolonged aging; the nanorods are attached each other using their {001}, {100}, and {110} crystal planes. With concentrated NaOH used in synthesis, the nanorods can also be extended along 〈100〉, which gives rise to the formation of CuO nanoplatelets. Various synthetic parameters have also been investigated.

C. Subramanian

Papers

Growth and characterization of antimony doped tin oxide thin films

Growth of zinc thiourea sulfate (ZTS) single crystals: a potential semiorganic NLO material

Crystallization and microhardness of calcium oxalate monohydrate

Synthesis of lanthanum aluminate by a citrate-combustion route

Ferroelectric characterization studies on barium calcium titanate single crystals