Electromagnetic and superconducting properties are considered in superconducting layers separated by interlayer with the thickness of the oxide layer 10-20 A (the so-called multilayer lattices of (S-D-S) n-type). In particular, the phenomenon of stimulation of superconductivity is expounded and specific dependence on the number of oxide evaporated layers and their thickness is obtained. The Josephson array defectivity is considered with the frustration parameter. The number of states in these models shows a wide variety of critical behavior as a function of the frustration f(0 <; f <; 1). The characteristics defined densities of electronic states of superconducting and normal-metal layers in S/N superlattice are presented. It is clear that even with the constant interaction conservation between the nearest layers, which in the same for all the layers, the frustration introduction over the layers result in a hysteresis in T_c (n), i.e., in the irreversibility phenomena so characteristic of high-temperature superconductors. The connection of this result with tunneling spectra of high-Tc superconductors such as Yba_2Cu_3O_(7-d), (YBCO) thin films deposited on LaAlO_3 substrates is observed.

Stimulation of Superconductivity in Submolecular Structures With Weakly Coupled Superconducting Layers

: This program was an outgrowth of our early empirical successes in forming superconducting tunnel junctions on thin films of the high transition temperature superconductors, specifically those in the so-called A15 class such as Nb3Sn (T(c) approx 18 K) and V3Si (T(c) approx 16 K) Prior to this all attempts at tunneling in the A15 superconductors had been on bulk material and were not widely successful Moreover such non-thin film junctions are of limited device interest As a result of this program we now have general junction formation techniques, apparently suitable for the A15 superconductors as a class, which are being routinely used for material diagnostics and for studies of the superconducting properties of these materials More importantly, perhaps, they appear to have important device potential We summarized only the main results and conclusions, referring the reader to the appendix for a more comprehensive discussion

M. R. Beasley

Papers

Superconducting Tunneling and Tunneling Applications in High Tc A15 Superconductors.