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arXiv · 1107.5796

Transition from columnar to point pinning in coated conductors: critical currents, that are independent of magnetic field direction

Yuri L. Zuev·Sung Hun Wee·David K. Christen
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Abstract

We identify a phase transition in the vortex system of a high-temperature superconductor with nano-columnar stacks of precipitates as strong vortex pinning centers. Above a particular, temperature-dependent field $B_X(T)$ the vortex response is no longer determined by the nano-columns, and is instead determined by point-like pinning. This phase transition leads to the change in the measured critical current density as a function of angle between the applied magnetic field and the nano-columns. Below the unbinding, there is a strong maximum in $J_C$ when field is aligned parallel to the columns. Above the unbinding, there is a minimum for this orientation.

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Yuri L. Zuev, Sung Hun Wee, David K. Christen. 2011-07-29. Transition from columnar to point pinning in coated conductors: critical currents, that are independent of magnetic field direction. https://doi.org/10.1088/0953-2048%2F25%2F7%2F075009

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