Thin-film flux transformers of YBa2Cu3O(7-x)
Abstract
Using a three layer in situ laser deposition process, superconducting thin film flux transformers were constructed of YBa2Cu3O(7-x) (YBCO). The transformers are designed for efficient coupling to a planar thin film dc SQUID, have 0.7 sq cm magnetic field pickup areas, and 10-turn input coils. When coupled to a low transition temperature (Tc) SQUID, the resulting hybrid magnetometer exhibits excess low frequency flux noise which arises in the transformer. This noise depends on the geometry of the flux transformer, and the observed behavior agrees with model calculations of the expected contribution from flux motion in the YBCO. The hybrid magnetometer attains a magnetic field sensitivity of about 0.9 pTHz(exp -1/2) at 1Hz with the transformer at 60K; the rms noise decreases as 1/f(exp 1/2) up to a frequency of (approx) 1kHz. It is believed that the sensitivity is high enough for use, for example, in magnetocardiography.
- Publication:
-
Astrophysical Processes and Structures in the Universe
- Pub Date:
- September 1990
- Bibcode:
- 1990apsu.confS..24W
- Keywords:
-
- Magnetic Fields;
- Squid (Detectors);
- Superconducting Films;
- Thin Films;
- Transformers;
- Barium Oxides;
- Copper Oxides;
- Deposition;
- Magnetometers;
- Yttrium Oxides;
- Solid-State Physics