PHASE-EQUILIBRIA AND CRYSTAL-CHEMISTRY IN THE QUATERNARY SYSTEM BA-SR-Y-CU-O IN AIR

Studies in the Sr-Y-Cu-O and Ba-Sr-Y-Cu-O systems have revealed that Sr will substitute for Ba in (Ba,Sr)2YCu3O6+x up to about 60%. There are no ternary compounds in the Sr-Y-Cu-O system equivalent to the three ternary phases in the Ba system. A new binary phase, 'Sr14Cu24O41' (CuO 63.158 mol%), was found which forms a solid solution with Y2O3 to a Sr:Y ratio of approximately 2:1. This phase can also incorporate considerable amounts of Ba and Ca and many other large ions.