The phenomenon of the penetration of a low-frequency weak magnetic field into a superconductor has stimulated extensive theoretical and experimental studies. These have led to important clarifications regarding the nature of the superconducting phase by, for example, making concrete the idea of the long-range order in terms of the coherence length, which in turn has provided an understanding of the details of the penetration phenomenon under various conditions realized for different relative values of the penetration depth and the coherence length. This work is a review of the theoretical and experimental studies of the penetration phenomenon. The theory of the penetration phenomenon is discussed phenomenologically and microscopically. Different experimental techniques employed to study the phenomenon are discussed. Many of the experimental studies are concerned with the temperature dependence of the penetration depth. These results are reviewed for different elemental superconductors. Practical difficulties in a quantitative analysis of such data are pointed out. A new strategy adopted recently by Egloffet al. for analyzing the penetration depth data of pure lead is discussed. Effects of impurities, anisotropy of the Fermi surface, and the magnetic field on the penetration phenomenon are also discussed.

Electrodynamics of superconductors. Response to a weak, low-frequency magnetic field

Two dimensional collective flux pinning in melt spun superconducting amorphous Zr70Cu30

Model relating superconductive penetration depth and metallurgical phase separation in amorphous La70Cu30

Superconducting behavior of amorphous Zr70Cu30

The surface magnetization has been obtained indirectly in superconducting NaHg4, by measuring the Ginzburg-Landau parameter K and the thermodynamic critical field Hc, at 2.50 K. Within the Abrikosov approximation, the current-carrying properties of the superconducting sheath have an associated magnetization per unit volume, which can be expressed as a function of k. We have determined this magnetization for cylindrical samples of radius R and size parameters R λ between 2.5 and 20. The dependence of the magnetization on the normalized magnetic field penetration depth gd λ has been established except for the region near the lower critical field.

On the surface magnetization in superconducting NaHg4

Superconducting penetration depth in amorphous metals

Surface normal regions in superconducting Zr70Cu30 induced by thermal relaxation

It is shown that weak field penetration depth measurements can be used to determine the change in the normal and superconducting behaviour of amorphous samples, when heat-treated below the crystallization temperature The results are used to discuss the validity of BCS-Gorkov relations, when applied to these materials

R. Arce

Papers

Superconducting penetration depth in amorphous metals

Surface normal regions in superconducting Zr70Cu30 induced by thermal relaxation

Superconducting penetration depth in amorphous La70 Cu30