Atomic structure of large-angle grain boundaries Sigma 5 and Sigma 3 in YBa2Cu3O7-delta and their transport properties

Article

关键词: REDUCED CRITICAL CURRENTS;    THIN-FILMS;    SUPERCONDUCTORS;    BICRYSTALS;   

DOI  :  10.1103/PhysRevB.64.224525

来源: SCIE

【 摘 要 】

We present the results of a computer simulation of the atomic structures of large-angle symmetrical tilt grain boundaries (GB's) Sigma5 (misorientation angles 36.87 degrees and 53.13 degrees) and Sigma 13 (misorientation angles 22.62 degrees and 67.38 degrees). The critical strain level epsilon (crit) criterion (phenomenological criterion) of Chisholm and Pennycook is applied to the computer simulation data to estimate the thickness of the nonsuperconducting layer h(n) enveloping the grain boundaries. The critical strain epsilon (crit) is derived from the strain field of a dislocation at the distance from its geometrical center where the lattice presumably becomes nontransparent for supercurrent. The epsilon (crit) determined this way is several times greater than the estimate given in earlier papers. The value of h(n) is estimated also by a bond-valence-sum analysis. The two approaches agree with each other. It is predicted that the symmetrical tilt GB Sigma5 theta = 53.13 degrees should demonstrate the largest critical current across the boundary.

【 授权许可】

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