Unusual Sequence of the Critical Magnetic Fields , , and in Multicomponent Superconductors.

All superconductors in a magnetic field are characterized by three critical magnetic fields: lower critical , upper critical and thermodynamic critical field . Only two sets of inequalities or are possible in a single-component superconductor. Here, we report our study of the critical fields in multicomponent superconductors with two superconducting components in the framework of the Ginzburg-Landau functional.

Macroscopic quantum tunneling in "small" Josephson junctions in a magnetic field.

We study the phenomenon of macroscopic quantum tunneling (MQT) in small Josephson junctions (JJ) with an externally applied magnetic field. The latter results in the appearance of the Fraunhofer type modulation of the current density along the barrier. The problem of MQT for a pointlike JJ is reduced to the motion of the quantum particle in the washboard potential.

Effect of vortex-antivortex fluctuations on the heat capacity of a type-II superconducting film.

The small size vortex-antivortex pairs proliferation in a type-II superconducting film is considered below T(c). The corresponding contribution to the free energy is calculated. It is shown that these fluctuations give the main temperature dependent contribution to the heat capacity of the superconducting film in the sufficiently large interval of temperatures below the transition point.