| Zugriffsnummer | 30367 |
| Dokumenttyp | Zeitschriftenartikel |
| Sprache | Englisch |
| Titel | Low‐frequency noise in low‐T c multiloop magnetometers with additional positive feedback |
| Autor(in); Institution |
Drung, Dietmar; 9.33, Kryoelektronik, PTB-Berlin
|
| Quelle/Jahr | Applied Physics Letters: 67 (1995), 10, 1474 - 1476 |
| ISSN | 0003-6951 |
| DOI | |
| Verlag | Melville, NY: AIP |
| Freie Schlagworte | magnetometers ; 1/f noise ; machinery noise ; materials fabrication ; quantum noise ; superconducting quantum interference devices |
| Zusammenfassung | The low‐frequency noise in multiloop dc superconducting quantum interference device(SQUID)magnetometersfabricated from low‐T sub.c (transition temperature) materials was investigated. The magnetometers are operated in a flux‐locked loop based on additional positive feedback (APF). A simple noise reduction scheme for dc SQUIDs with APF is presented that eliminates the influence of critical current and resistance fluctuations without deteriorating the white noise performance. Applying this scheme to a magnetometer with a low‐frequency two‐level switching due to a single trap in the Si x N y tunnel barrier reduced the switching amplitude of ≂10−3 Φ0 by at least two orders of magnitude down to a level below the intrinsic magnetometer flux noise. Using simple direct‐coupled readout electronics with a 10 kHz bias reversal, a high bandwidth of ≂1 MHz, a low white flux noise of 1.5×10−6 Φ0/√Hz, and a 1/fnoise corner frequency of 4 Hz have been measured. |
