VOLUME DEPENDENCE OF THE SUPERCONDUCTING TRANSITION-TEMPERATURE FOR THE HIGH-TEMPERATURE SUPERCONDUCTOR HGBA2CA2-XPBXCU(3)O(8+DELTA)

The homologous series HgBa2Can-1CunO2n+2+delta (n = 1 2, 3, 4) is the newest and most promising of the layered high-T-c superconducting mate rials, as demonstrated in setting the highest T-c among the known supe rconducting materials. We slightly doped HgBa2Ca2Cu3O8+delta with Pb, producing HgBa2Ca2-zPbzCU3O8+delta with T-c about 133 K. The Pb dopant helped material growth and still kept T-c close to that of the optima lly doped HgBa2Ca2Cu3O8+delta The superconducting transition temperatu re as a function of pressure, T-c(P), was measured to 3 GPa. T-c incre ases monotonically with dT(c)(P)/dP approximate to 1.5 K/GPa near ambi ent pressure. The lattice parameters as a function of pressure were me asured to 5 GPa. The volume decreases monotonically and is represented by an isothermal bulk modulus of B-v = 143 +/- 15 GPa. Both results w ere combined to produce T-c(V), which is readily comparable to theoret ical models.