Response of fractal penetration of magnetic flux to disorder landscape in superconducting films

Article

关键词: CRITICAL-CURRENT DENSITY;    MGB2/MG NANO-COMPOSITES;    SLOW COMBUSTION;    CRITICAL-STATE;    THICK-FILMS;    DEPOSITION;    INVASION;    PAPER;   

DOI  :  10.1103/PhysRevB.72.134514

来源: SCIE

【 摘 要 】

Magnetic flux front and induction contours in superconducting YBa2Cu3O7-delta films with defect size s similar to xi (superconducting coherence length) and s >>xi are studied by magneto-optical imaging. Robust self-affine spatial correlation was observed using scaling analysis in the small pinning disorder-dominated (s similar to xi) films. The roughness exponent alpha was determined to be similar to 0.66, independent of numbers of defects (or the film thickness). When the disorder landscape also included a distribution of large defects (s >xi), the flux front and induction contours exhibited self-similarity, with a fractal dimension D determined to be similar to 1.33 using the box-counting method. The remarkably different flux penetration patterns were shown to be the manifestation of self-organized criticality at different length scales.

【 授权许可】

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