Influence of some metallic additives on the flux trapping ability of high temperature superconducting ceramics

Abstract

By applying magnetic fields on high temperature superconducting (HTS) bulks, superconducting permanent magnets (SPMs) can be produced. Two relevant factors influencing the properties of the SPMs have been investigated: 1. The external magnetic field to be trapped by HTS bulks—that depends on the mode of the magnetization (static or pulse form). 2. The flux trapping ability of the HTS bulks (that is, which percentage of the external magnetic field can be trapped by the HTS materials)—that depends on and can be controlled by the composition and the preparation technique of the HTS bulks. YBaCuO base single domain bulks with CeSn and Ce + Ag additives were prepared aiming at the analyse of the influence of these additives on the flux trapping ability of Y 1Ba 2Cu 3O 7− x (Y123) superconducting bulks. In the reported stage of our long term R&D work we focused on the pulse magnetization of these superconducting bulks. A pulse generator equipped with set of magnetizing coils have been designed and built for supplying various pulse forms for magnetizing the bulks. Using this pulse magnetization equipment, a magnetic flux density as high as 4.0 T could be created by discharging a capacitor bank through ignitron switches into the magnetizing coil. The equipment is capable to generate variable pulse shapes. The YBCO bulk samples were magnetized in zero field cooled (ZFC mode). For cooling the samples, liquid nitrogen was used. The pulse magnetized bulks were measured and tested by field mapping.