Flicker (1/f) noise in the critical current of Josephson junctions at 0.09-4.2 K

被引:57
作者
Wellstood, FC
Urbina, C
Clarke, J [1 ]
机构
[1] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[2] Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA
关键词
D O I
10.1063/1.1826236
中图分类号
O59 [应用物理学];
学科分类号
摘要
We have measured the low-frequency noise in the critical current I-c of six dc superconducting quantum interference devices (SQUIDs) with resistively shunted Nb-NbOx-PbIn Josephson junctions in the temperature range T=0.09-4.2 K. Each device is voltage biased, the applied flux is an integer number of flux quanta, and the current fluctuations are measured with a second dc SQUID. At low frequencies f, there is a component of the power spectrum of the critical current fluctuations given approximately by S-Ic(f)=(CIcT2)-T-2/Af, where A is the area of both junctions, and Capproximate to(3.9+/-0.4)x10(-23) m(2)/K-2. For quantum bits based on Josephson junctions, the scaling of S-Ic(f) with T-2 implies that the dephasing time limited by critical current l/f noise should scale as 1/T for temperatures down to at least 0.09 K. (C) 2004 American Institute of Physics.
引用
收藏
页码:5296 / 5298
页数:3
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