Shielding effects in ceramic superconductors

✍ Scribed by Halina Niculescu; Rainer Schmidmeier; Betina Topolski; Peter J. Gielisse

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 590 KB
• Volume: 229
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)90818-4

✦ Synopsis

The shielding properties of high-temperature superconductors in DC and AC magnetic fields are discussed using Bean's critical-state model and models, which account for the field dependence of the critical current density.

Experimental work on the shielding properties of superconducting YBa2Cu307_,~ and conductive (aluminum and copper) screens is presented. The maximum value of the shielded field for YBa2Cu3OT_JAg screens was measured at 3 mT. Shielding by superconducting screens was found independent of frequency over the range 80 Hz-105 Hz.

The limited shielding capability of ceramic superconductors results from the magnetic field dependence and low values of the intergrain current density in bulk materials. There is a practical limit to the external field that can be shielded by a superconductor, characteristic of the material and size independent. Increasing of the shield thickness will not increase the maximum value of the field which can be shielded.