He used Ginzburg–Landau theory to explain experiments on superconducting alloys and thin films. The most important finding from Ginzburg–Landau theory was made by Alexei Abrikosov in 1957. Most pure elemental superconductors, except niobium and carbon nanotubes, are Type I, while almost all impure and compound superconductors are Type II. The mixed state is actually caused by vortices in the electronic superfluid, sometimes called fluxons because the flux carried by these vortices is quantized. At a second critical field strength H c2, superconductivity is destroyed. In Type II superconductors, raising the applied field past a critical value H c1 leads to a mixed state (also known as the vortex state) in which an increasing amount of magnetic flux penetrates the material, but there remains no resistance to the flow of electric current as long as the current is not too large. Depending on the geometry of the sample, one may obtain an intermediate state consisting of a baroque pattern of regions of normal material carrying a magnetic field mixed with regions of superconducting material containing no field. In Type I superconductors, superconductivity is abruptly destroyed when the strength of the applied field rises above a critical value H c. Superconductors can be divided into two classes according to how this breakdown occurs. The Meissner state breaks down when the applied magnetic field is too large. On the energy of the interface between the normal and superconducting states. In the original paper Ginzburg and Landau observed the existence of two types of superconductors depending In quantum mechanics the particle probability flow density J p (unit: particles per second per m 2), also called probability current, can be derived from the Schrödinger equation to be The average number is proportional to Δ V and ΨΨ ∗ is now interpreted as the particle density. The number will fluctuate but the fluctuations around the average are relatively small.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |