超伝導入門
第9章: ギンスブルグ-ランダウ理論 (4)
2000 年 35 巻 12 号 p. 568-574
詳細
2000 年 35 巻 12 号 p. 568-574
Together with the problem of the boundary energy in the intermediate state described in the previous chapter, one of the main objects of the Ginzburg-Landau (GL) theory was the analysis of the nature of the transition between superconducting and normal states by the magnetic field. In the London theory, the number density of the superconducting electrons, ns, which plays the role of the order parameter is assumed to be constant throughout the superconductor and depends only on the temperature. In contrast, the order parameter in the GL theory, which by difinition is related to the number density, ns, may change over the GL coherence length and also depends on the magnetic field, as described by the GL equation. In this chapter, calculations made by GL on the magnetization and the nature of the magnetic transition of thin superconducting films will be described.
