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Direct-coupled micro-magnetometer with Y-Ba-Cu-O nano-slit SQUID fabricated with a focused helium ion beam.

  • Author(s): Cho, Ethan Y
  • Li, Hao
  • LeFebvre, Jay C
  • Zhou, Yuchao W
  • Dynes, RC
  • Cybart, Shane A
  • et al.

Published Web Location

https://aip.scitation.org/doi/abs/10.1063/1.5048776
No data is associated with this publication.
Abstract

Direct write patterning of high-transition temperature (high-T C) superconducting oxide thin films with a focused helium ion beam is a formidable approach for the scaling of high-T C circuit feature sizes down to the nanoscale. In this letter, we report using this technique to create a sensitive micro superconducting quantum interference device (SQUID) magnetometer with a sensing area of about 100 × 100 μm2. The device is fabricated from a single 35-nm thick YBa2Cu3O7- δ film. A flux concentrating pick-up loop is directly coupled to a 10 nm × 20 μm nano-slit SQUID. The SQUID is defined entirely by helium ion irradiation from a gas field ion source. The irradiation converts the superconductor to an insulator, and no material is milled away or etched. In this manner, a very narrow non-superconducting nano-slit is created entirely within the plane of the film. The narrow slit dimension allows for maximization of the coupling to the field concentrator. Electrical measurements reveal a large 0.35 mV modulation with a magnetic field. We measure a white noise level of 2 μΦ0/Hz1∕2. The field noise of the magnetometer is 4 pT/Hz1∕2 at 4.2 K.

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