Noise performance of high-T/sub c/ DC SQUID magnetometers
| Autor: | H. Zhou, M.B. Burbank, W. Westera, J. Chrzanowski, P.R. Kubik, P. Brown, X.M. Burany, F. Habib, A.E. Curzon, V. Angus, S. Govorkov, B. Heinrich, J. Nomura, M. Smith, K. Ferguson, R A Cragg, K. Betts, J. Vrba, G. Anderson, P. Spear, Weibing Xing, J.C. Irwin, Christopher J. Backhouse, A.A. Fife |
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| Rok vydání: | 1995 |
| Předmět: |
Materials science
High-temperature superconductivity Magnetometer business.industry Infrasound Biasing Low frequency Condensed Matter Physics Noise (electronics) Electronic Optical and Magnetic Materials law.invention Nuclear magnetic resonance Electromagnetic coil law Scanning SQUID microscopy Optoelectronics Electrical and Electronic Engineering business |
| Zdroj: | IEEE Transactions on Appiled Superconductivity. 5:3113-3118 |
| ISSN: | 1051-8223 |
| DOI: | 10.1109/77.403251 |
| Popis: | High-T/sub c/ DC SQUID magnetometers operating at 77 K have been fabricated from epitaxial YBCO and SrTiO/sub 3/ films and characterized. The DC SQUID washers incorporated either bicrystal or step-edge microbridge junctions of widths down to about 3 /spl mu/m. Three types of DC SQUID magnetometer are described-(a) a single layer device with a direct-coupled loop; (b) a DC SQUID plus flip-chip coupled flux transformer; (c) a fractional turn device with a direct-coupled multi-loop. The 1/f noise in the spectra of uncoupled DC SQUIDs and some magnetometers is significantly reduced by using AC bias modulation. Low frequency energy sensitivities of uncoupled SQUIDs at 77 K have been improved by use of AC bias to 7/spl times/10/sup -30/ J/Hz at 1 Hz (45 pH inductance). For flip-chip coupled magnetometers (15-turn input coil, pick-up coil area 13 mm/sup 2/), excess low frequency noise was observed, only partially reduced by AC biasing, with field sensitivities of 1 pT rms//spl radic/(Hz) and 130 fT rms/spl radic/(Hz) above 200 Hz. > |
| Databáze: | OpenAIRE |
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