Preparation and characterisation of PbSr(YCa)CuO superconducting crystals

Basic magnetic properties of Pb sub 2 Sr sub 2 Y sub 1--x Ca sub x Cu sub 3 O sub 8+ delta have been studied. Results of the measurements of the AC susceptibility of the powder samples with x = 0.2-0.8 and DC magnetic moment and susceptibility of the Pb sub 2 Sr sub 2 Y sub 0.7 Ca sub 0.3 Cu sub 3 O sub 8+ delta single crystal are presented. Temperature dependence of the magnetic moment in various cooling procedures was measured. Zero-field cooling (ZFC), field cooling (FC) and remanent (REM) magnetic moments are given. A lower critical field H sub c1 has been determined for the magnetic field oriented perpendicular (H sub perpindicular to ) and parallel (H sub || ) to the Cu--O planes. A new more sensitive procedure of H sub c1 determination has been proposed. Graphs. 9 ref.--AA