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In superconductivity, an '''Abrikosov vortex''' is a vortex of [[supercurrent]] in a [[type-II superconductor]] theoretically predicted by [[Alexei Alexeyevich Abrikosov|Alexei Abrikosov]] in 1957.<ref>Abrikosov, A. A. (1957). [http://www.sciencedirect.com/science/article/pii/0022369757900835 The magnetic properties of superconducting alloys]. [[Journal of Physics and Chemistry of Solids]], 2(3), 199-208.</ref> The [[supercurrent]] circulates around the normal (i.e. non-superconducting) core of the vortex. The core has a size <math>\sim\xi</math> — the [[superconducting coherence length]] (parameter of a [[Ginzburg-Landau theory]]). The supercurrents decay on the distance about <math>\lambda</math> ([[London penetration depth]]) from the core. Note that in [[type-II superconductors]] <math>\lambda>\xi</math>. The circulating [[supercurrent]]s induce magnetic fields with the total flux equal to a single [[magnetic flux quantum|flux quantum]] <math>\Phi_0</math>. Therefore, an Abrikosov vortex is often called a [[fluxon]]. | |||
The magnetic field distribution of a single vortex far from its core can be described by | |||
<center><math> | |||
B(r) = \frac{\Phi_0}{2\pi\lambda^2}K_0\left(\frac{r}{\lambda}\right) | |||
\approx \sqrt{\frac{\lambda}{r}} \exp\left(-\frac{r}{\lambda}\right), | |||
</math></center> | |||
where <math>K_0(z)</math> is a zeroth-order [[Bessel function]]. Note that, according to the above formula, at <math>r \to 0</math> the magnetic field <math>B(r)\propto\ln(\lambda/r)</math>, i.e. logarithmically diverges. In reality, for <math>r\lesssim\xi</math> the field is simply given by | |||
<center><math> | |||
B(0)\approx \frac{\Phi_0}{2\pi\lambda^2}\ln\kappa, | |||
</math></center> | |||
where ''κ'' = ''λ/ξ'' is known as the Ginzburg-Landau parameter, which must be <math>\kappa>1/\sqrt{2}</math> in [[type-II superconductor]]s. | |||
Abrikosov vortices can be trapped in a [[type-II superconductor]] by chance, on defects, etc. Even if initially [[type-II superconductor]] contains no vortices, and one applies a magnetic field <math>H</math> larger than the [[Upper critical field#Lower critical field|lower critical field]] <math>H_{c1}</math> (but smaller than the [[upper critical field]] <math>H_{c2}</math>), the field penetrates into superconductor in terms of '''Abrikosov vortices'''. Each vortex carries one thread of magnetic field with the flux <math>\Phi_0</math>. Abrikosov vortices form a lattice (usually triangular, may be with defects/dislocations) with the average vortex density (flux density) approximately equal to the externally applied magnetic field. | |||
==See also== | |||
* [[Ginzburg-Landau theory]] | |||
* [[Type-II superconductor]] | |||
* [[Alexei Alexeyevich Abrikosov]] | |||
* [[Macroscopic quantum phenomena]] | |||
* [[Pinning force]] | |||
* [[Flux pinning]] | |||
==References== | |||
{{Reflist}} | |||
[[Category:Superconductivity]] | |||
[[Category:Vortices]] |
Revision as of 21:44, 29 November 2013
In superconductivity, an Abrikosov vortex is a vortex of supercurrent in a type-II superconductor theoretically predicted by Alexei Abrikosov in 1957.[1] The supercurrent circulates around the normal (i.e. non-superconducting) core of the vortex. The core has a size — the superconducting coherence length (parameter of a Ginzburg-Landau theory). The supercurrents decay on the distance about (London penetration depth) from the core. Note that in type-II superconductors . The circulating supercurrents induce magnetic fields with the total flux equal to a single flux quantum . Therefore, an Abrikosov vortex is often called a fluxon.
The magnetic field distribution of a single vortex far from its core can be described by
where is a zeroth-order Bessel function. Note that, according to the above formula, at the magnetic field , i.e. logarithmically diverges. In reality, for the field is simply given by
where κ = λ/ξ is known as the Ginzburg-Landau parameter, which must be in type-II superconductors.
Abrikosov vortices can be trapped in a type-II superconductor by chance, on defects, etc. Even if initially type-II superconductor contains no vortices, and one applies a magnetic field larger than the lower critical field (but smaller than the upper critical field ), the field penetrates into superconductor in terms of Abrikosov vortices. Each vortex carries one thread of magnetic field with the flux . Abrikosov vortices form a lattice (usually triangular, may be with defects/dislocations) with the average vortex density (flux density) approximately equal to the externally applied magnetic field.
See also
- Ginzburg-Landau theory
- Type-II superconductor
- Alexei Alexeyevich Abrikosov
- Macroscopic quantum phenomena
- Pinning force
- Flux pinning
References
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- ↑ Abrikosov, A. A. (1957). The magnetic properties of superconducting alloys. Journal of Physics and Chemistry of Solids, 2(3), 199-208.