Theory of the upper critical field of superconducting superlattices

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.33.4620· OSTI ID:6121938

Takahashi, S; Tachiki, M

The upper critical field of superconducting superlattices is calculated by taking account of spatial variations of the following quantities of conduction electrons: the density of states, the diffusion constant, the attractive interaction constant responsible for superconductivity, and the spin polarization. For applied magnetic fields parallel to the layers, these spatial variations cause a dimensional crossover in the temperature dependence of the upper critical field H/sub c/2X. The spatial variation of the density of states is most important for the effect of the dimensional crossover observed in Nb/Cu superlattices. For applied magnetic fields perpendicular to layers, a new type of crossover is predicted in the temperature dependence of H/sub c/2perpendicular for superlattices composed of a high-H/sub c/2 material and a low-H/sub c/2 material. The anisotropic spin polarization of conduction electrons induced by applied magnetic fields explains the anomalous behavior of H/sub c/2 observed in V/Ni superlattices.

• Research Organization: The Research Institute for Iron, Steel and Other Metals, Tohoku University, Katahira, Sendai 980, Japan
• OSTI ID: 6121938
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 33:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
COPPER ALLOYS
CRITICAL FIELD
DIFFUSION LENGTH
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY-LEVEL DENSITY
EVALUATION
LENGTH
MAGNETIC FIELDS
NICKEL ALLOYS
NIOBIUM ALLOYS
ORIENTATION
PHYSICAL PROPERTIES
PROXIMITY EFFECT
SPIN ORIENTATION
SUPERCONDUCTIVITY
SUPERLATTICES
VANADIUM ALLOYS