HIGH-PRESSURE STUDY OF RSR2CU2.7MO0.3OY WITH R=SM, EU, GD, TB, DY, HO, ER, TM, AND YB

The hydrostatic-pressure effect on the superconducting transition temp erature (T(c)) of the stabilized Sr-based 1:2:3 compounds RSr2Cu2.7Mo0 .3Oy with R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb has been determin ed up to 16 kbar. All T(c)'s are enhanced linearly by pressure at a ra ther rapid rate (dT(c)/dP). A drastic jump in dT(c)/dP vs ionic radius of R occurs near Dy, i.e., dT(c)/dP approximately 0.7K/kbar for small R = Ho, Er, Tm, and Yb, and approximately 0.4 K/kbar for the larger R 's = Tb, Gd, Eu, and Sm. The results suggest that Cu(1) substitution b y Mo is crucial in the stabilization of the Sr-based 1:2:3 compound. S everal possibilities for the dT(c)/dP step detected are advanced.