Investigation of microwave properties of superconducting Nb/sub 0/ /sub 4/Ti/sub 0/ /sub 6/

Conference · Sat Mar 01 04:00:00 EDT 1975 · IEEE Trans. Magn.; (United States)

OSTI ID:7366967

Giordano, S ^[1]; Hahn, H; Halama, H J; Luhman, T S; Bauer, W

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1. Brookhaven National Lab., Upton, NY

A superconducting Nb/sub 0/./sub 4/Ti/sub 0/./sub 6/ test cavity was constructed to measure the surface losses as function of frequency in the range from 2 to 8 GHz and as a function of temperature below 4.2 K. The temperature-dependent part of the surface resistance agrees essentially with the BCS theory if the material parameters T/sub c/ = 9.8 K, ..delta..(0) = 1.73 k/sub B/T/sub c/, xi/sub 0/ = 380 A, lambda/sub L/ = 310 A, and l = 4 to 8 A are taken. The magnitude and frequency dependence of the temperature-independent residual resistance observed in the niobium titanium cavity suggests no difference in the behavior of type I and II superconductors. The highest Q/sub 0/ = 2.9 x 10/sup 9/ was measured in the TE/sub 011/ mode at 3.9 GHz. A coaxial cavity with removable sample was constructed for an in-depth study of rf breakdown and its relationship with metallurgical parameters as characterized by ac loss, magnetization, and penetration depth measurements. Peak fields in solid type-II superconducting cavities are limited by their low thermal conductivity, suggesting the use of films, 0.01 to 0.1 mm thick, on pure niobium or copper. The highest magnetic field (120 G) was measured on a recrystallized sample, suggesting that the lower critical field, H/sub cl/, (for this sample 75 G) does not prevent the application of high-T/sub c/ type-II superconductors to microwave devices. (auth)

• NSA Number: NSA-33-17034
• OSTI ID: 7366967
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: MAG-11:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AC LOSSES
ALLOYS
BCS THEORY
CAVITY RESONATORS
CRITICAL FIELD
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FREQUENCY DEPENDENCE
FREQUENCY RANGE
GHZ RANGE
GHZ RANGE 01-100
MAGNETIC FIELDS
NIOBIUM ALLOYS
PHYSICAL PROPERTIES
QUALITY FACTOR
SUPERCONDUCTING CAVITY RESONATORS
SUPERCONDUCTING DEVICES
SUPERCONDUCTIVITY
TITANIUM ALLOYS
TITANIUM BASE ALLOYS
ULTRALOW TEMPERATURE