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In superconductivity, a Pearl vortex is a vortex of supercurrent in a thin film of type-II superconductor, first described in 1964 by Judea Pearl. A Pearl vortex is similar to Abrikosov vortex except for its magnetic field profile which, due to the dominant air-metal interface, diverges sharply as 1/ at short distances from the center, and decays slowly, like 1/ at long distances. Abrikosov's vortices, in comparison, have very short range interaction and diverge as near the center. A transport current flowing through a superconducting film may cause these vortices to move with a constant velocity proportional to, and perpendicular to the transport current. Because of their proximity to the surface, and their sharp field divergence at their centers, Pearl's vortices can actually be seen by a scanning SQUID microscope. The characteristic length governing the distribution of the magnetic field around the vortex center is given by the ratio /, also known as "Pearl length," where is the film thickness and is London penetration depth. Because this ratio can reach macroscopic dimensions (~1 mm) by making the film sufficiently thin, it can be measured relatively easy and used to estimate the density of superconducting electrons. At distances shorter than the Pearl's length, vortices behave like a Coulomb gas (1/ repulsive force). ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pearl vortex」の詳細全文を読む スポンサード リンク
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