Flicker (1/f) Noise in 45^± Bi-Epitaxial Grain Boundary Junctions and dc SQUID of YBa2Cu3Oy

B. C. Yao；S. H. Tsai；C. C. Chi；M. K. Wu

Chinese Journal of Physics

38卷2S期（2000 / 04 / 01）

273 - 278

英文

We have fabricated dc superconducting quantum interference devices (SQUIDs) incorporating 45℃ bi-epitaxial grain boundary junction, i.e. YBCO/YSZ and YBCO/YBCO/YSZ, in washer geometry. The 1/f noise power of single junction comes from resistance fluctuation for high current bias and critical current fluctuation for low current bias. The noise spectrum of the dc SQUIDs was measured with dc and ac bias schemes and showed value of ～ 1X10^-5 Φ 0/Hz^1/2 at 100 Hz. The possible noise sources, critical current fluctuations, flux motion noise and resistance fluctuation, are investigated. The results are compared with previous published data.