Yttrium Barium Cuprate

There is on record at least one investigation leading to the emulsion synthesis of YBa2Cu307 x powders [207]. The basic solvent system was Tween 85, poly(oxyethylene) sorbitan ester/kerosene (oil phase). The aqueous phase containing dissolved salts Ba(N03)2, Cu(N03)2.3H20 and Y(N03)3.H20 in proper proportions was added into the surfactant/oil system under stirring which was continued for several hours after the addition was complete. An ultrasonic disruptor was used for decreasing the aqueous droplet size. This emulsion was added drop by drop into hot (180 C) kerosene. The product powders were washed with toluene 

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Lately high-temperature superconductors with rare-earth ions in their structure have been widely investigated. These compounds are based on antiferromagnetic dielectrics (yttrium-barium cuprates, cuprates of lanthanum or neodimium, etc.) having a distinctive lamellar structure which defines the peculiarities of magnetic interactions and magnetic ordering in the system of rare-earth ions. 

Rozental O.M., Fotiev V.A., Avvakumov E.G., Fedanchin E.l. Mechanosynthesis of yttrium and barium cuprates. Proc. All-Union Scientific and Technological Conference Mechanochemical synthesis , Vladivostok, 1990 112-14. 

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. 

A common feature of all the new ceramic superconductors is that they are cuprates, that is, they are complex copper oxides. The structure of YBCO is given in Fig. 19.3, which also shows that it is related to the perovskite structure (Fig. 4.17). Synthesis of YBCO is remarkably easy appropriate amounts of dry yttrium oxide (Y203), copper oxide (CuO), and barium carbonate (BaC03) are ground together into a fine, well-mixed... 

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