The influence of the structure on the electrical and magnetic properties of Bi2Sr2CaCu2O8+δ single crystals

The correlation between the structure, chemical composition, electrical and magnetic properties of Bi2Sr2CaCu2O8+δ single crystals is presented. As revealed by SEM measurements, the small samples (approximately 1 mm×1 mm×0.2 mm) are stacks of thin plates (1–2 μm). Microcompositional measurements (energy dispersive spectroscopy) show the Bi2Sr2CaCu2O8+δ (2212)-phase and a small quantity of residual phases enriched in bismuth and strontium and calcium-deficient. Magnetically modulated microwave absorption measurements (MAMMA) lead to a value for the anisotropy of the upper critical field of about 7, which is more than twice the reported value for YBa2Cu3O7-δ single crystals (also determined from MAMMA responses). The plot of the resistance versus temperature suggests that only the first 10–20 plates from the surface of the sample have a contribution to the sample conductivity. The imaginary part, X″, of the magnetic susceptibility of our samples shows three peaks. This revised version was published online in November 2006 with corrections to the Cover Date.