Thermal Fluctuations in Pb-Ag-Pb (SNS) Josephson Junctions in Magnetic Fields

元データ 1985-08-15 社団法人日本物理学会


A systematic investigation of the thermal fluctuation effects has been carriedout on Pb -Ax -Pb (surerconductor-normal metal-surerconductor) Josephsonjunctions with special emphasis on the critical current l.(H) in magnetic fields.Thick normal-metal barriers ( - 15000 A) are prepared in ot'der to suppress theJosephson coupling energy between the two superconductors. Thermal fluctuationscan significantly break the superconducting phase coupling and then lead to adecrease of the oscillation amplitude of l.(H). In the presence of strong fluctuations,the envelope of the maxima in the Fraunhofer diffraction pattern is proportionalto l /H' and not to I /H as in the absence of thermal fluctuations. The experimentalresults are in agreement with theoretical predictions of Ivanchenko and Zil'berman.


NAGATA Shoichi Department of Materials Science and Engineering, Muroran Institute of Technology
Nagata S Muroran Inst. Technol. Hokkaido
Nagata S Kumakoto Univ. Kumamoto Jpn
Nagata Shoichi Department Of Applied Material Science Muroran Institute Of Technology