High temperature superconductors structural aspects

Among the high-temperature superconductors one finds various cuprates (i.e., ternary oxides of copper and barium) having a layered structure of the perovskite type, as well as more complicated oxides on the basis of copper oxide which also include oxides of yttrium, calcium, strontium, bismuth, thallium, and/or other metals. Today, all these oxide systems are studied closely by a variety of specialists, including physicists, chemists, physical chemists, and theoreticians attempting to elucidate the essence of this phenomenon. Studies of electrochemical aspects contribute markedly to progress in HTSCs. 

Rao, C. N. R. (ed.) 19886 Chemical and structural aspects of high-temperature superconductors. Singapore World Scientific. 

SOME STRUCTURAL-ELECTRONIC ASPECTS OF HIGH TEMPERATURE SUPERCONDUCTORS... 

Some Structural-Electronic Aspects of High Temperature Superconductors 207... 

Electron microscopy techniques are essential tools needed for the investigation of the local structure and composition of grain boundaries in high-temperature superconductors. While we have emphasized structural aspects here, analytical characterizations (see Chapters 8 and 11) are extremely important and must be part of establishing direct connections to transport properties. 

The first step towards the fabrication of thin-film devices is the growth of a single-layer film. The anisotropic layered structure and short superconducting coherence lengths of most high Tc superconductors introduce aspects of film growth that need not to be considered for conventional low-temperature superconductors. 

A rather different approach from that given above will be found in Three theories of superconductivity by F. A. Matsen, J. Chem. Educ. (1987) 64, 842. The structural patterns associated with superconductivity are well illustrated in The Crystal Chemistry of High-Temperature Oxide Superconductors and Materials with Related Structures by H. Miiller-Buschbaum, Angew. Chem., Int. Ed. Engl. (1989) 28, 1472. A mixture of structure and some theory is to be found in a very readable, non-mathematical, article Some Structural-Electronic Aspects of High Temperature Superconductors , by J. K. Burdett, in Adv. Chem. Phys. (1993) 83, 207. 

Structure-property relations and other aspects of the oxide superconductors that I have described so far should clearly indicate how chemistry becomes important in not only synthesizing novel materials of desired structures and properties, but also in understanding the phenomenon of high-temperature superconductivity. Our... 

Irrespective of whether we understand why these systems are superconductors or not (at present we appear to be a long way off this goal), the large number of detailed structural and physical studies that have been made in recent years of these oxides have provided us with an unprecedented opportunity to explore in detail aspects of chemistry and physics which just would not have been possible with the large, but woefully inadequate set of observations available to us a decade ago. This article will therefore not be a review of high temperature superconductivity, per se, neither will it be comprehensive, but really some explorations into how nature controls the structure and metallic properties of oxide materials, a vital first step in generating a superconductor. It will begin... 

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