CRITICAL PARAMETERS OF HIGH-TEMPERATURE H GBACACUO CERAMICS WITH T-C=133 K - EFFECTS OF MAGNETIC-FIELD AND PRESSURE

The dependences of critical temperature T-c and critical current densi ty J(c) on hydrostatic compression up to 10 kbar for the Hg0.8Pb0.2Ba2 Ca2Cu3O8+delta (Hg1223) ceramics are studied. The rate of variation in dT(c)/dP is 0.28+/-0.04 K/kbar for pressures up to 3 kbar and decreas es to 0.18+/-0.04 K/kbar at P approximate to 10 kbar. This nonlinearit y seems to be due to the variation in hole concentration in the CuO2 p lanes influenced by pressure. The observed strong response of the crit ical current to pressure (d ln J(c)/dP = 0.2+/-0.02 koap(-1)) points t o a weak-linked character of a transporting cluster in the ceramics un der investigation.