Microscopic disorder and first flux penetration in ceramics
Résumé
YBa2Cu3O7−δFx ceramics with 0 ≤ x ≤ 0.14 and δ= 0 and 0.3 display first penetration fields H1(T)∝(1-T/Tc)2.7. A classical London approach together with a fractal cluster model explain this result.