The 60- and 90-K superconductivity in $\mathrm{Eu}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ has been investigated under pressures up to 16 kbar. Unusually large pressure effects on the normal-state resistivity and the superconducting transition temperature of the 60-K compound were observed in contrast to the 90-K one. A subtle difference between the 30-, 60-, and 90-K superconductors is therefore proposed.

• Received 9 November 1987

DOI:https://doi.org/10.1103/PhysRevB.37.9730