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arXiv · 1705.06166

Nearly quantum limited nanoSQUIDs based on cross-type Nb/AlOx/Nb junctions

M. Schmelz·V. Zakosarenko·T. Schönau·S. Anders·S. Linzen·R. Stolz·H. -G. Meyer
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Abstract

We report on the development of nearly quantum limited SQUIDs with miniature pickup loop dimensions. The implemented high quality and low capacitance cross-type Nb/AlOx/Nb Josephson junctions offer large $I_CR_N$-products and therefore enable an exceptional low noise level of the SQUIDs. Devices with loop dimensions of 1 {\mu}m exhibit white flux noise levels as low as $45 n{\Phi}_0/Hz^{1/2}$ corresponding to an energy resolution {\epsilon} of about 1 h at 4.2 K, with h being Plancks constant. Moreover, the large usable voltage swings of the devices of about 300 {\mu}V allow highly sensitive and easy single-stage operation while exploring nearly the intrinsic noise of the SQUIDs, beneficial e.g. for sensor arrays in SQUID microscopy.

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M. Schmelz, V. Zakosarenko, T. Schönau, S. Anders, S. Linzen, R. Stolz, H. -G. Meyer. 2017-05-17. Nearly quantum limited nanoSQUIDs based on cross-type Nb/AlOx/Nb junctions. https://doi.org/10.1088/0953-2048/30/1/014001

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