Temperature dependence of submillimeter wave response in the point-contact Josephson junction

Conference · Fri Mar 01 04:00:00 EST 1985 · IEEE Trans. Magn.; (United States)

OSTI ID:6485372

Morita, S; Imai, S; Mikoshiba, N; Senoh, T

The authors have measured the magnitude of the first Shapiro step in both bridge-type (Ta-Ta and Ta-Sn) and tunneltype (Ta-SnOx-Sn) point-contact Josephson junctions in the SMMW (Submillimeter Wave) region. By varying the temperature continuously with the frequency of the SMMW fixed (..omega..=2..pi../lambda, lambda=699, 570 and 469 ..mu..m), we determined I/sub 1/ /SUP MAX/ /I /SUB c/ minutely as a function of the normalized frequency ..omega../..omega.. /SUB g/ (T), where I/sub 1/ /SUP MAX/ is the maximum (half) height of the first Shapiro step as a function of the ac field power, I /SUB c/ is the critical current, and ..omega.. /SUB g/ (T)=4..delta.. /SUB Ta/ (T)/h or 2(..delta.. /SUB Ta/ (T)+..delta.. /SUB Sn/ (T))/h. By fitting the shape of the Riedel peak at ..omega../..omega.. /SUB g/ (T)=1 with the theory of the tunnel junction, we have determined the damping factor delta. They obtained delta=0.02 for the Ta-SnOx-Sn tunnel - type junction, and delta=0.05 for both the Ta-Sn and Ta-Ta bridge - type junctions, respectively. At ..omega../..omega.. /SUB g/ (T)>1.5, we have found that I/sub 1/ /SUP MAX/ /I /SUB c/ tends to saturate in both the tunnel-type and the bridge-type junctions as ..omega../..omega.. /SUB g/ (T) increases. For the tunnel-type junction, this agrees with the very slow decrease predicted by the theory of the tunnel junction. But for the bridge-type junction, this slow decrease is in marked contrast to the very rapid decrease found from the previous experiments, where the Shapiro step was measured for a number of frequencies at a fixed temperature.

• Research Organization: Research Institute of Electrical Communication, Tohoku University, Sendai
• OSTI ID: 6485372
• Report Number(s): CONF-840937-
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: MAG-21:2
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
CHALCOGENIDES
JOSEPHSON JUNCTIONS
JUNCTIONS
OXIDES
OXYGEN COMPOUNDS
SUPERCONDUCTING JUNCTIONS
TANTALUM ALLOYS
TEMPERATURE DEPENDENCE
TEMPERATURE MEASUREMENT
TIN ALLOYS
TIN COMPOUNDS
TIN OXIDES