Werner Herkert

Preparation and magnetic properties of high Tc (110 K) Bi-Sr-Ca-Cu-oxide superconductors

Abstract Polycristalline samples of Bi-Sr-Ca-Cu-oxide with a large volume fraction of the 110 K phase have been prepared from oxide mixtures with the atomic ratio being 4:3:3:6. The structure of the plate-like grains can be described as a sequence of 2212 and 2223 layers. DC magnetization measurements clearly indicate that 95% of the flux expulsion due to the Meissner effect result from the 2223 (110 K) phase.

Status of HTS activities at SIEMENS

Abstract The work on YBa 2 Cu 3 O 7 (1-2-3) at SIEMENS has established (i) processes for high quality (1-2-3) films on SrTiO 3 or on ZrO 2 by sputtering or laser evaporation respectively, (ii) a hypersonic spraying process to lay down (1-2-3) thick films on steel tubing, (iii) analytical tools for precise monitoring of the oxygen content in (1-2-3) and for the investigation of the defect structure on an atomic scale in films and bulk material, (iv) test wires of competitive but still moderate current densities, and (v) inductive test methods for homogeneity of films and procedures to form electrical contacts of low resistivity.