Reexamination of the ${\mathrm{Y}}_2$${\mathrm{O}}_3$-BaO-CuO phase diagram for solid solutions near ${\mathrm{Y}}_1$${\mathrm{Ba}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_7$

In a previous communication the results of critical-temperature and Hall-effect measurements on compounds off the stoichiometric ${\mathrm{Y}}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ composition were interpreted as an indication that a narrow range of solid solutions exists for the superconducting compound. Present data show that the earlier results were due to oxygen deficiency in the off-stoichiometry samples and that no evidence exists for solid solutions off or on the 50%-Cu line between ${\mathrm{Y}}_2$ ${\mathrm{Cu}}_2$ ${\mathrm{O}}_5$-BaCu${\mathrm{O}}_2$ of the ternary ${\mathrm{Y}}_2$ ${\mathrm{O}}_3$-BaO-CuO phase diagram.