Title :
Preparation and performance of toroidal Y1Ba2Cu3O7-x-RF SQUIDs
Author :
Zhang, Y. ; Diegel, M. ; Heiden, C.
Author_Institution :
Inst. fuer Angewandte Phys., Justus-Liebig-Univ., Giessen, West Germany
fDate :
3/1/1989 12:00:00 AM
Abstract :
Starting from disk-shaped bulk specimens of Y1Ba2 Cu3O7-x with Tc near 90 K, RF SQUIDs (superconducting quantum interference devices) to toroidal topology with a permanently adjusted mill-bridge contact were prepared. Contact trimming was done by reducing the cross section so that a good SQUID signal was obtained at 77 K. The SQUIDs were sealed after the adjustment in order to prevent degradation by moisture. Using conventional 20-MHz readout electronics the SQUIDs were operated in the flux-locked loop mode. Flux noise of the order of 10-4 Φ 0/√Hz was obtained at 77 K in the white region of the spectrum, with excess noise below about 100 Hz. The devices are quite robust due to their monolithic structure and demonstrate good stability against thermal cycling
Keywords :
SQUIDs; barium compounds; electron device noise; high-temperature superconductors; yttrium compounds; RF SQUIDs; Y1Ba2Cu3O7-x; contact trimming; flux noise; flux-locked loop mode; high temperature superconductor; monolithic structure; permanently adjusted mill-bridge contact; thermal cycling stability; toroidal topology; white region; Circuit topology; Degradation; Moisture; Radio frequency; Radiofrequency interference; Readout electronics; Robust stability; SQUIDs; Superconducting device noise; Superconducting devices;
Journal_Title :
Magnetics, IEEE Transactions on
