A high Tc dc superconducting quantum interference device (SQUID) was fabricated using a bicrystal junction with a misorientation angle of θ = 30°. The junction with a width of 2 μm exhibited high resistance Rs = 10Ω and critical current I0 = 25 μA at T = 77 K. This gives a I0Rs as high as 250 μV. These values indicate that the bicrystal junction has great potential for the development of high performance SQUIDs. The SQUID fabricated with a 30° junction exhibited voltage modulation depths as high as ΔV = 85 μV, 40 μV and 20 μV at T = 77 K for the inductance values of Ls = 60 pH, 100 pH and 160 pH, respectively. These are the highest values reported so far. Preliminary noise measurement showed that the flux noise of the SQUID is less than 8 μΦ0/Hz1/2 for the white noise region, and less than 70 μΦ0/Hz1/2 at f = 1 Hz when the 60 pH-SQUID is dc biased and operated with a conventional Flux Locked Loop (FLL) circuit.
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Issue number||8 SUPPL. B|
|Publication status||Published - Aug 15 1997|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)