Operation of rf SQUID magnetometers with a multi-turn flux transformer integrated with a superconducting labyrinth resonator

• Published in: IEEE transactions on applied superconductivity Vol. 9; no. 2; pp. 3396 - 3400
• Main Authors: Zhang, Y., Yi, H.R., Schubert, J., Zander, W., Krause, H.-J., Bousack, H., Braginski, A.I.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.1999; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Coiling; Coils; COPPER OXIDE; Couplings; CRYSTAL GROWTH; ELECTRONIC PRODUCTS; Electronics; EPITAXY; Exact sciences and technology; Flux; FLUXES; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Labyrinth; Magnetic circuits; Magnetic components, instruments and techniques; Magnetic noise; Magnetometers for magnetic field measurements; Physics; Radio frequency; Resonators; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; SQUID magnetometers; SQUIDs; Superconducting device noise; Superconducting devices; Superconducting epitaxial layers; Superconducting films; Superconducting quantum interference devices; SUPERCONDUCTIVITY; SUPERCONDUCTORS; Transformers; White noise; YTTRIUM OXIDE; Experimental result; Magnetometers; Superconducting resonator; Superconducting quantum interferometer device; White noise; Epitaxial film; Flip chip; Radiofrequency; Magnetic field; Planar technology
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/77.783758

This paper demonstrates a design of a planar multi-turn flux transformer integrated with a superconducting labyrinth resonator serving as the planar tank circuit for a radio frequency (rf) superconducting quantum interference device (SQUID) magnetometer. All structures were patterned from 200 nm-thick epitaxial YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) films grown on 10/spl times/10 mm/sup 2/ LaAlO/sub 3/ substrates. A double-hole washer SQUID had one hole coupled to the input coil of the labyrinth resonator and the other hole coupled to the input coil of the multi-turn flux transformer using a flip-chip configuration to form a magnetometer. This resonator has a good high-frequency coupling to the double-hole rf SQUID, thus securing its optimum operation. For the voltage-to-flux (transfer function) coefficient, a value of 300-500 /spl mu/V//spl Phi//sub 0/ was obtained. A SQUID magnetometer with an inductance of 210 pH exhibited white flux noise of 11.5 /spl mu//spl Phi//sub 0///spl radic/Hz at 77 K. This corresponded to a white magnetic field noise of 11.5 fT//spl radic/Hz.