CA-43 NMR-STUDY OF BISMUTH-BASED HIGH-T(C) SUPERCONDUCTORS

As a first step of a study of the electronic properties of CuO2 planes by probing calcium nuclei in the bismuth-based high-T(c) materials we report here the structural assignment of Ca NMR lines measured in Ca- 43-enriched samples of n = 2 ((Bi,Pb)2Sr2CaCu2O8+x) and n = 3 ((Bi,Pb) 2Sr2Ca2CU3O10+x) bismuth compounds. Powdered samples were investigated as well as oriented powders, achieved by uniaxial alignment of the gr ains in a 7T magnetic field. For the main calcium site (Ca between two CuO2 planes), we could determine the quadrupolar as well as the shift tensors. The results indicate that, in the same way as yttrium nuclei in YBaCuO, calcium nuclei are sensitive to the magnetic susceptibilit y of the metallic CuO2 planes.