Directly coupled direct current superconducting quantum interference device magnetometers based on ramp-edge Ag:YBa2Cu3O7−x/PrBa2Cu3O7−x/Ag:YBa2Cu3O7−x junctions
Directly coupled dc superconducting quantum interference device (SQUID) magnetometers on LaAlO3 substrates were fabricated using ramp-edge superconductor/normal-metal/superconductor junctions, where Ag-doped YBa2Cu3O7−x was used for the electrode and PrBa2Cu3O7−x for the normal-metal barrier. A flux...
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Veröffentlicht in: | Applied physics letters 1998-06, Vol.72 (23), p.3068-3070 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Directly coupled dc superconducting quantum interference device (SQUID) magnetometers on LaAlO3 substrates were fabricated using ramp-edge superconductor/normal-metal/superconductor junctions, where Ag-doped YBa2Cu3O7−x was used for the electrode and PrBa2Cu3O7−x for the normal-metal barrier. A flux noise of 8×10−6 Φ0 Hz−1/2 at 10 kHz measured with a dc bias current was achieved at 75 K, which corresponded to a field sensitivity of 400 fTHz−1/2 for a magnetometer with a pick-up loop area of 8.5 mm×7.5 mm. Most significantly, the noise floor increased at lower frequencies with a frequency dependence slightly less than 1/f. The field noise of the SQUID magnetometers increased by only 25% after cycling the devices from zero field to 500 mG. In a static earth’s magnetic field background, the field noise of the SQUID magnetometers increased by less than a factor of 2. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.121543 |