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A CONTACTLESS METHOD FOR MEASUREMENT OF THE CRITICAL CURRENT DENSITY AND CRITICAL TEMPERATURE OF SUPERCONDUCTING FILMS.

Author(s) : CLAASSEN J. H., REEVES M. E., SOULEN R. J. Jr

Type of article: Article

Summary

A NEW METHOD FOR MEASURING THE CRITICAL CURRENT DENSITY AND TRANSITION TEMPERATURE OF A SUPERCONDUCTING FILM WITHOUT MAKING CONTACT TO IT CONSISTS OF POSITIONING A FLAT, MULTITURN COIL NEAR THE FILM SURFACE AND DRIVING THE COIL WITH AN AUDIO FREQUENCY SINE-WAVE CURRENT. INDUCED SHIELDING CURRENTS FLOW IN THE FILM. THE INDUCED CURRENT DENSITY IS ZERO AT THE COIL CENTER, RISES TOA MAXIMUM NEAR THE MEAN RADIUS OF THE DRIVE COIL, AND THEN FALLS OFF RAPIDLY AS THE RADIUS CONTINUES TO INCREASE. A MEASUREMENT OF THE CRITICAL CURRENT PER LENGTH CAN BE OBTAINED BY MONITORING THE DEVELOPMENT OF ODD HARMONIC VOLTAGE COMPONENTS. THE CRITICAL CURRENT OBTAINED BY THIS INDUCTIVE MEASUREMENT HAS BEEN DEMONSTRATED TO GIVE NEARLY THE SAME VALUE AS THAT OBTAINED BY A TRANSPORT MEASUREMENT.

Details

  • Original title: A CONTACTLESS METHOD FOR MEASUREMENT OF THE CRITICAL CURRENT DENSITY AND CRITICAL TEMPERATURE OF SUPERCONDUCTING FILMS.
  • Record ID : 1992-0953
  • Languages: English
  • Source: Rev. sci. Instrum. - vol. 62 - n. 4
  • Publication date: 1991/04
  • Document available for consultation in the library of the IIR headquarters only.

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