Physics:Pearl vortex
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.[1] 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/[math]\displaystyle{ r }[/math] at short distances from the center, and decays slowly, like 1/[math]\displaystyle{ r^2 }[/math] at long distances. Abrikosov's vortices, in comparison, have very short range interaction and diverge as [math]\displaystyle{ \log(1/r) }[/math] near the center.
A transport current flowing through a superconducting film may cause these vortices to move with a constant velocity [math]\displaystyle{ v }[/math] proportional to, and perpendicular to the transport current.[2] 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.[3][4][5] The characteristic length governing the distribution of the magnetic field around the vortex center is given by the ratio [math]\displaystyle{ \Lambda = 2 \lambda^2 }[/math]/[math]\displaystyle{ d }[/math], also known as "Pearl length," where [math]\displaystyle{ d }[/math] is the film thickness and [math]\displaystyle{ \lambda }[/math] is London penetration depth.[6] 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.[5]
At distances shorter than the Pearl's length, vortices behave like a Coulomb gas (1/[math]\displaystyle{ r }[/math] repulsive force).
References
- ↑ Pearl, Judea (1964). "Current distribution in superconducting films carrying quantized fluxoids". Applied Physics Letters 5 (4): 65–66. doi:10.1063/1.1754056. Bibcode: 1964ApPhL...5...65P.
- ↑ Kogan, V.G.; Nakagawa, N. (2021). "Moving Pearl vortices in thin-film superconductors". arXiv:2102.00073 [cond-mat.supr-con].
- ↑ Tafuri, F.; J.R. Kirtley; P.G. Medaglia; P. Orgiani; G. Balestrino (2004). "Magnetic Imaging of Pearl vortices in Artificially layered [math]\displaystyle{ (Ba_{0.9}Nd_{0.1}CuO_{2+x})_m/(CaCuO_2)_n }[/math] Systems". Physical Review Letters 92 (15): 157006. doi:10.1103/PhysRevLett.92.157006. PMID 15169312. Bibcode: 2004PhRvL..92o7006T. https://art.torvergata.it/bitstream/2108/33451/1/PRL%20Tafuri%202004.pdf.
- ↑ Pozzi, G. (2007). "Electron optical effects of a Pearl vortex near the film edge". Physical Review B 76 (54510): 054510. doi:10.1103/PhysRevB.76.054510. Bibcode: 2007PhRvB..76e4510P.
- ↑ 5.0 5.1 Bert, Julie A.; Beena Kalisky; Christopher Bell; Minu Kim; Yasuyuki Hikita; Harold Y. Hwang; Kathryn A. Moler (2011). "Direct imaging of the coexistence of ferromagnetism and superconductivity at the [math]\displaystyle{ LaAIO_3/SrTiO_3 }[/math] interface". Nature Physics 7 (10): 767––771. doi:10.1038/nphys2079. Bibcode: 2011NatPh...7..767B.
- ↑ Clem, John R. (2010). "Josephson junctions in thin and narrow rectangular superconducting strips". Physical Review B 81 (14): 144515. doi:10.1103/PhysRevB.81.144515. Bibcode: 2010PhRvB..81n4515C.
 |  |
