Superconductivity, localization, and interaction effects in Nb/sub 0. 53/Ti/sub 0. 47/-Ge superlattices

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6268361

Jin, B Y

The sputter deposited, Nb/sub 0.53/Ti/sub 0.47/-Ge superlattice system is investigated in this work. The physical properties of these superlattices are found to depend strongly on both the superconducting Nb/sub 0.53/Ti/sub 0.47/ and insulating Ge layer thicknesses. A three-dimensional (3D) to two-dimensional (2D) crossover in the parallel upper critical field (H/sub c2parallel/) is observed as the Nb/sub 0.53/Ti/sub 0.47/ layer thickness (D/sub s/) is systematically decreased to below 200 A (with the Ge layer thickness kept constant at about 30 A), or as the Ge layer thickness (D/sub Ge/) is increased to above 25 A (with D/sub s/ = 95A). The zero temperature, parallel upper critical field of the films showing 2D behavior is estimated. The estimated H/sub c2parallel/(0) peaks at about 40 tesla for a superconducting layer thickness of 144 A. This rather high upper critical field is considerably above the bulk value of 14.5 tesla. On decreasing the Nb/sub 0.53/Ti/sub 0.47/ layer thickness, the superconducting transition temperature is found to decrease rapidly and roughly proportional to R//sub 0//sup -1/. This phenomenon is attributed to the effect of localization and to the interaction effect.

• Research Organization: Northwestern Univ., Evanston, IL (USA)
• OSTI ID: 6268361
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
CRITICAL FIELD
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EXPERIMENTAL DATA
FILMS
GERMANIUM
INFORMATION
MAGNETIC FIELDS
METALS
NIOBIUM ALLOYS
NUMERICAL DATA
PHYSICAL PROPERTIES
SUPERCONDUCTIVITY
SUPERLATTICES
THIN FILMS
TITANIUM ALLOYS