UHF HIGH-Tc SQUID

Abstract

For the first time we have designed, constructed and investigated an UHF high-T c SQUID pumped at 360 MHz at 77 K. The SQUID is based on an one-hole interferometer with a microbridge Josephson contact made of bulk YBaCuO ceramics by the standard technique of mechanical scribing, followed by finishing with a high-voltage discharge electroerrosion. Magnetic flux sensitivity of the UHF SQUID as measured by the output signal of a quadratic detector with a dc amplifier of 40 kHz bandwidth was found to be about 5 × 10−5ϕ0/ Hz 1/2 in the quasiwhite noise region (at a frequency over 700 Hz).