Investigations of chemical interaction between Bi-based 2212 and (RE)Ba2Cu3O7 high Tc superconducting materials

Composite materials have been synthesized by mixing 90% (or 95%) YBa2Cu3O7 and 10% (or 5%) Bi2Sr2Ca1Cu2O8 by weight, and firing at 900°C to promote grain growth by inducing a liquid phase (Bi2Sr2Ca1Cu2O8) in the system. The influence of the amount of liquid phase on the X-ray diffraction data and electrical properties is reported. Energy dispersive X-ray (EDX) analyses are also reported. The YBiBa2O6 phase is formed during the heat treatment and introduces additional chemical heterogeneities at the grain boundaries. A previously reported 2212-related superconducting phase, Bi2(Sr,Ba)2(Ca,Y)Cu2O8+y, could also be formed during the synthesis process, and its effect on the electrical resistance versus temperature measurements is discussed. Attempts to substitute RE ions (Dy3+, Er3+, Ho3+) for Y3+ in YBiBa2O6 have been successful and are reported in an appendix section. X-ray diffraction data are also reported. EDX analyses have been performed specifically for a typical ErBiBa2O6 compound and reveal the presence of a new Er2Ba4O7 phase. © 1993.