Theory of the upper critical field of superconducting superlattices
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), Vol. 33:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER ALLOYS
CRITICAL FIELD
SUPERCONDUCTIVITY
NICKEL ALLOYS
NIOBIUM ALLOYS
SUPERLATTICES
VANADIUM ALLOYS
DIFFUSION LENGTH
ENERGY-LEVEL DENSITY
EVALUATION
MAGNETIC FIELDS
PROXIMITY EFFECT
SPIN ORIENTATION
ALLOYS
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
LENGTH
ORIENTATION
PHYSICAL PROPERTIES
360104* - Metals & Alloys- Physical Properties
656102 - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)