Bismuth-based superconductor

The volatility of the reactants is a concern in some solid state syntheses. This may be a slight problem in bismuth cuprates synthesized at high temperatures because Bi2Os has an appreciable vapor pressure at these temperatures (i.e. 900-950°C) however, chemical analyses of samples of bismuth-based superconductors before and after reactions at temperatures up to 900°C indicate no detectable loss of bismuth. This problem is much more severe in the case of thallium chemistry. 

A method that can distinguish between the oxidation states Cus+ and Bi5+ in bismuth-based superconductors has been described (33). Bi5+ (BiOs") can oxidize Mn2+ to Mn04", while Cus+ is not a strong enough oxidizing agent to accomplish this task. 

The Chemistry of High Tc in the Bismuth Based Oxide Superconductors BaPbi.xBix03 and Bai xKxBi03... 

Bismuth Based Oxide Superconductors BaPbj.jjB Og and Ba1.xKxBi03 349... 

Bismuth Based Oxide Superconductors BaPbj B Oj and Ba1.xKxBi03 351... 

Bismuth Based Oxide Superconductors BaPbl xBix03 and Ba1.xKxBi03 353... 

Bismuth Based Oxide Superconductors BaPb1.xBix03 and Ba1.xKxBi03 355... 

This discovery stimulated what can only be described as frenzied research in many laboratories throughout the world which quickly resulted in the discovery of YBa2Cu307, the so-called T23 phase, or YBCO, with a transition at a temperature as high as 93 K. There are also bismuth-based high-Tc superconductors, which are described below. 

Maeda, H. and Togano, K. (eds) (1996) Bismuth-based High-Temperature Superconductors, Marcel Dekker, Inc., New York. 

One of main thrusts in organic-perovskite hybrids has been in the preparation of stable delaminated perovskite sols as the building blocks of nanocomposite materials. A well-known process for exfoliation is to weaken the attractive interaction of the layers through intercalation of bulky organic components. A representative example is exfoliation of bismuth-based cuprate superconductors (Figure 14.12). °3... 

Since the discovery of high temperature superconductivity (T > 30 K) in the La-Ba-Cu-O system hundreds of high temperature superconducting oxides have been found, with the record Tc of 164 K in Hg-1223 under high pressure. According to their major chemical difference, these superconductors can be classified into six major categories K2Nip4-type cuprates, rare-earth-based cuprates, bismuth-based cuprates, thallium-based cuprates, mercury-based cuprates, and other cuprates. Details of every superconductor are not presented, but at least one typical composition of each major type will be discussed in detail. Interested readers can read the relevant literature to get specific information on other systems. 

Preparation of Superconductive Ceramics 17.3.10.2. High Temperature Superconductors 17.3.10.2.3. Bismuth-Based Cuprates. 

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