Coherence transition and the irreversibility line in granular YBCO

✍ Scribed by Frederik Wolff Fabris; Paulo Pureur

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 284 KB
• Volume: 408-410
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2004.03.112

✦ Synopsis

We report on resistivity and magnetization experiments near the superconducting transition of ceramic YBCO. The resistive transition proceeds in two steps. We focus on the coherence transition, where the phases of the order parameter in individual grains become long-range ordered and the zero-resistance state sets in. We show that the fluctuation conductivity obeys a characteristic scaling behavior which is indicative of the thermodynamic nature of this transition. We interpret the irreversibility line in low fields as an ergodicity breaking limit related to the glass-like behavior of the granular array.