Accession Number : AD0469135


Title :   DEPENDENCE OF THE CRITICAL CURRENTS IN SUPERCONDUCTING FILMS ON APPLIED MAGNETIC FIELD AND TEMPERATURE,


Corporate Author : STEVENS INST OF TECH HOBOKEN NJ DEPT OF PHYSICS AND ENGINEERING PHYSICS


Personal Author(s) : Mydosh, J A ; Meissner, Hans


Report Date : Jan 1965


Pagination or Media Count : 44


Abstract : Measurements of critical currents were performed on planar and cylindrical films of tin of 650 to 2500 A thickness. Both pulsed currents (80 nanoseconds duration) and dc currents with stabilizing network were used. Close agreement was obtained for the dc data in the temperature dependence and approximate agreement in the magnitude of the critical current when compared with Bardeen's calculation as long as the stabilizing network was effective. The pulse measurments deviate from theory and the dc data for temperatures T/T sub c .9. Oscilloscope pictures of the transitions indicate that this deviation towards lower currents is not caused by usual Joule heating. This and other similar work with pulsed currents and fields would indicate that an entirely new mechanism is responsible for the discrepancy in fast pulsed critical currents. Critical current measurements were also taken with the superposition of external magnetic fields H sub e. The whole range from the critical current in zero field to the critical field as measured with a current of 100 microamps was covered. (Author)


Descriptors :   *METAL FILMS , SUPERCONDUCTORS , TIN , MAGNETIC FIELDS , ELECTRIC CURRENT , ELECTROMAGNETIC PULSES , TEMPERATURE , CRYOGENICS , MATHEMATICAL ANALYSIS


Distribution Statement : APPROVED FOR PUBLIC RELEASE