Upper critical magnetic field of superconducting films with magnetic impurities

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6203495

Lemberger, T R

We have measured the upper critical magnetic field, H/sub c2/(T), of In-Mn and Pb-Mn alloy films. H/sub c2/ was determined from the resistance of the films. The results were compared with the theory of Fulde and Maki. This theory assumes that the electron-phonon coupling is weak, and that the interaction between the impurity spins and the conduction electron spins is weak. The theory predicts that the pair-breaking effect of the magnetic impurities is temperature-independent, and that the pair-breaking effects of the magnetic impurities and the applied magnetic field are additive. Furthermore, it predicts explicitly the temperature dependence of H/sub c2/. The temperature dependence of H/sub c2/ for the In-Mn alloy films is well described by the Fulde-Maki theory, despite the moderately strong electron-phonon coupling and the strong interaction between the impurity spins and the conduction electron spins. The temperature dependence of H/sub c2/ for the Pb-Mn alloy films is not well described by the Fulde-Maki theory, probably due to the strong electron-phonon coupling in Pb. However, even without a quantitatively correct theory, one can conclude from the Pb-Mn data that the pair-breaking effect of the magnetic impurities is temperature independent, and that the pair-breaking effects of the magnetic impurities and the applied magnetic field are additive. For some of the Pb-Mn alloy films, there was a region of positive curvature in H/sub c2/(T) near the zero-field transition temperature. This positive curvature is not understood.

• Research Organization: Illinois Univ., Urbana (USA)
• OSTI ID: 6203495
• 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
CRITICAL FIELD
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON-PHONON COUPLING
EXPERIMENTAL DATA
FILMS
INDIUM ALLOYS
INFORMATION
LEAD ALLOYS
MAGNETIC FIELDS
MANGANESE ALLOYS
NUMERICAL DATA
PHYSICAL PROPERTIES
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE