Critical current relaxation in ceramic superconductors effect of the surface barrier

✍ Scribed by K.I. Kugel; A.L. Rakhmanov

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 531 KB
• Volume: 251
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00397-5

✦ Synopsis

The effect of the Bean-Livingston surface barrier on the thermoactivated relaxation of magnetization and critical current in superconducting ceramics is analyzed. The following picture of flux dynamics is discussed. At first, magnetic flux penetrates into intergranular regions, and then flux lines overcome the barrier and enter the granules owing to thermally assisted flux motion. Such a thermal relaxation appreciably affects the magnetic flux distribution giving rise to time dependence of the intergranular magnetic field H o. The variation of H o results in the relaxation of the critical current Jc. The relaxation rates of H o and jc in increasing and decreasing magnetic field are calculated. These rates are shown to have clearly pronounced hysteretic behavior due to asymmetry in flux entering and leaving the granules.