Abstract
We have made sensitive dc superconducting quantum interference device (SQUID) magnetometers that operate at 77 K have been made. By using bicrystal grain boundary Josephson junctions and a single layer of YBa2Cu 3O7 thin film with optimized processing and an optimized directly coupled design, we have produced magnetometers with very low noise and a large transfer function. At 77 K, the transfer function is 100 μV/Φ0; the white field noise of the magnetometer is less than 10 fT/Hz above 10 kHz, rising to 26 fT/Hz at 1 Hz. The corresponding white noise energy has the low value of 2×10-31 J s; a value very similar to that of commercial Nb SQUIDS. Key elements required to achieve this performance are discussed.
Original language | English |
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Pages (from-to) | 3058 |
Number of pages | 1 |
Journal | Applied Physics Letters |
Volume | 66 |
DOIs | |
State | Published - 1995 |