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Multilayer Nb0.53Ti0.47/Ge superlattices with varying Nb0.53Ti0.47 and Ge layer thickness were sputter deposited on sapphire substrates at 200°C. The physical properties of these superlattices depend on the Nb0.53Ti0.47 layer thickness which is in turn related to the degree of disorder of the metal layer. The spectrum of samples can be subdivided roughly into three regions according to their different transport properties—a superconducting region, a weak localization region and a strong localization region. The sheet resistance, R□ of films in the weak localization region is in the range of 300ω The magnetoresistance is anisotropic for both the weakly and strongly localized films with the perpendicular magnetoresistance always larger than the parallel values. The weak localization to strong localization transition is consistent with the theoretically predicted mobility edge near R□≂ħ/0.12e2≅30kω.

Sandwich and superlattice structures composed of the high critical field superconducting alloy Nb0.53Ti0.47 (where the compositions refer to weight percent) and amorphous Ge were sputter‐deposited on sapphire substrates using a novel multi‐sputter‐gun system. The thicknesses of both the superconducting Nb0.53Ti0.47 and the insulating Ge layers were varied over a wide range in order to study the two‐dimensional (2D) and three‐dimensional (3D) superconducting properties of these structures. The observed suppression of the measured resistive superconducting transition temperature Tc with increasing sheet resistance is tentatively interpreted using the Maekawa–Fukuyama theory which incorporates contributions from localization and Coulomb interaction effects. The upper critical fields, with the field both normal Hc2⊥ and parallel Hc2∥ to the film, were measured up to 50 kG. Hc2∥ exhibited 2D behavior when the thickness of the superconducting layer was less than 200 A. The zero temperature values of Hc2∥(0) wer...

The growth and structural characteristics of three semiconductor-semimetal superlattices are presented. The superlattices were prepared by thermal evaporation in high vacuum. Although the constituents in each system have different crystal structures, only a small lattice mismatch (

We have studied the superconducting properties of V/Cr superlattices. Superlattices of V100Crx, V150Crx, and V200Crx, with x varying between 3 and 80 atomic planes have been prepared. The films have a strong (110) texture and were grown on sapphire substrates at 250°C in an ultra-high vacuum system. The zero field transition temperature of the V150Crx and V200Crx, but not the V100Crx films have been adequately modeled using Werthamer's theory for proximity effect coupled films. The films have a dimensional crossover in the parallel upper critical field when the thickness of the Cr layers is about 60 atomic planes.

The surface wave velocity in SnTe/Sb superlattices has been determined using Brillouin scattering. The velocity is independent of modulation wavelength over the range studied but is lower than would be expected if the layers of Sb and SnTe possessed their bulk properties. This is consistent with x‐ray data which can be interpreted as evidence of a cubic polymorph of Sb which is unstable in bulk form.

Some novel superconductor-insulator superlattice systems, Nb 0.53 Ti 0.47 Ge, Nb 0.53 Ti 0.47 Si and Nb 3 SnGe were synthesized with the dc sputtering technique. The parallel upper critical fields at zero temperature of these superlattices were estimated to be many times larger than their respective bulk values, due to the quasi-2D nature of the superconducting layers and associated fluxoid accomodation within the insulating layers. The disorder related quantum effects of weak anti-localization, electron interaction and superconducting fluctuations were also observed in these superlattices. The experimental data were compared with recent theories and the analysis provided microscopic information on these quasi-2D superconductors.