Koji Kajimura – författare

Since the First International Symposium on Superconductivity (ISS ''88) was held in Nagoya, Japan in 1988, significant advances have been achieved in a wide range of high temperature superconductivity research. Although the T c''s of recently discovered oxide superconductors still do not exceed the record high value of 125K reported before that meeting, the enrichment in the variety of materials should prove useful to the investigation of the fundamental mechanism of superconductiv­ ity in these exotic materials. The discovery of the n-type superconducting oxides proved to oppose the previously held empirical fact that the charge carriers in all oxide superconductors were holes. In addition, optimization of the charge carrier density has been established as a technique to improve the superconducting proper­ ties of the previously known oxide materials. Many new experimental and theoreti­ cal advances have been made in understanding both the fundamental and the applied aspects of high temperature superconductivity. In this latter area, various new processing techniques have been investigated, and the critical current densities and other significant parameters of both bulk and thin film oxide superconductors are rapidly being improved. At this exciting stage of research in high temperature superconductivity, it is extremely important to provide an opportunity for researchers from industry, academia, government and other institutions around the world to freely exchange information and thus contribute to the further advancement of research.

Since the First International Symposium on Superconductivity (ISS '88) was held in Nagoya, Japan in 1988, significant advances have been achieved in a wide range of high temperature superconductivity research. Although the T c's of recently discovered oxide superconductors still do not exceed the record high value of 125K reported before that meeting, the enrichment in the variety of materials should prove useful to the investigation of the fundamental mechanism of superconductiv­ ity in these exotic materials. The discovery of the n-type superconducting oxides proved to oppose the previously held empirical fact that the charge carriers in all oxide superconductors were holes. In addition, optimization of the charge carrier density has been established as a technique to improve the superconducting proper­ ties of the previously known oxide materials. Many new experimental and theoreti­ cal advances have been made in understanding both the fundamental and the applied aspects of high temperature superconductivity. In this latter area, various new processing techniques have been investigated, and the critical current densities and other significant parameters of both bulk and thin film oxide superconductors are rapidly being improved. At this exciting stage of research in high temperature superconductivity, it is extremely important to provide an opportunity for researchers from industry, academia, government and other institutions around the world to freely exchange information and thus contribute to the further advancement of research.

Since the discovery of high temperature superconductors, many new materials have been invented. In the last year, several new materials were also discovered, but their critical temperatures are still below lOOK. Precise physical and chemical work has made tremendous progress in the theoretical and experimental study of physical properties and carrier state characterizations. The de Haas van Alphen effect measurement showed the existence of a Fermi surface in YBCO. Flux dynamics is a well-known new problem in which flux creep and irreversibility line features are especially important for a fundamental understanding of the critical current and flux pinning. Flux pinning centers which are intentionally added using non-superconducting precipitates, neutrons, and protons, etc. increase critical currents to practical levels. The analysis of electric and magnetic properties are expected to reveal the pinning mechanism and also to further application development. As for wires and bulks, many melt-like sintering techniques have improved the material performance of critical current densities. A new seeding Quench-Melt­ Growth technique enlarged crystal size and increased the repulsion force. These melting processes, in conjunction with a mechanical strength improvement have been effectively introduced into wire fabrication in order to realize kilometer range wires and will put the oxide wires to practical use. Where thin film is con­ cerned, when many fabrication methods had been developed using the assistance effect of activated oxygen such as ozone and oxygen radicals, a high current 2 density of 106A/cm at 77K was reported.

Materials and Measurements in Molecular Electronics presents new developments in one of the most promising areas of electronics technology for the 21st century. Conjugated polymers, carbon clusters, and many other new molecular materials have been synthesized or discovered in recent years, and some now are on the threshold of commercial application. In the development of molecular materials, detailed knowledge of the structures and electronic states of molecular aggregates is essential. The focus of this book is on the development of new molecular materials and measuring techniques based on modern spectroscopy; included are such topics as Langmuir-Blodgett films, cluster materials, organic conductors, and conjugated electroluminescent polymers.