Flux quantization
Encyclopedia
Flux quantization is a quantum phenomenon in which the magnetic field
is quantized in the unit of
,
also known variously as flux quanta, fluxoids, vortices or fluxon
s.
Flux quantization occurs in Type II superconductors subjected to a magnetic field. Below a critical field Hc1, all magnetic flux is expulsed according to the Meissner effect
and perfect diamagnetism is observed, exactly as in a Type I superconductor
. Up to a second critical field value, Hc2, flux penetrates in discrete units while the bulk of the material remains superconducting. Both critical fields are temperature dependent, and tabulated values are the zero-temperature extrapolation unless otherwise noted.
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
is quantized in the unit of
,also known variously as flux quanta, fluxoids, vortices or fluxon
Fluxon
In physics, a fluxon is a quantum of electromagnetic flux. The term may have any of several related meanings.- Superconductivity :In the context of superconductivity, a fluxon is a small whisker of normal phase surrounded by superconducting phase. Supercurrents circulate around its center...
s.
Flux quantization occurs in Type II superconductors subjected to a magnetic field. Below a critical field Hc1, all magnetic flux is expulsed according to the Meissner effect
Meissner effect
The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. The German physicists Walther Meissner and Robert Ochsenfeld discovered the phenomenon in 1933 by measuring the magnetic field distribution outside superconducting tin...
and perfect diamagnetism is observed, exactly as in a Type I superconductor
Type I superconductor
Superconductors cannot be penetrated by magnetic flux lines . This Meissner state breaks down when the applied magnetic field is too large. Superconductors can be divided into two classes according to how this breakdown occurs...
. Up to a second critical field value, Hc2, flux penetrates in discrete units while the bulk of the material remains superconducting. Both critical fields are temperature dependent, and tabulated values are the zero-temperature extrapolation unless otherwise noted.