![A multiloop dc SQUID from 2 YBCO layers and an intermediate STO insulation layer. The diameter is 7 mm. The smallest structures on this chip are 3 µm wide.](http://kreynet.de/wp-content/uploads/2016/01/wh1.jpg)
The multilayer magnetometers described here are based on two superconducting YBa2Cu3O7 layers and an intermediate SrTiO3 layer for their insulation. Both types of thin-films are deposited by off-axis rf magnetron sputtering in an Ar/O2 atmosphere. The patterning of the thin-films is done by conventional photolithography and Ar-ion beam etching. Single layer magnetometers have also been prepared by a pulsed laser deposition process using a 248 nm KrF Excimer laser.
Multilayer Technology
![SEM micrograph of the central part of a multi loop magnetometer in multilayer technology.](http://kreynet.de/wp-content/uploads/2016/01/multiloopSEM.png)
Pulsed Laser Deposition
![Laser ablation plume while depositing a YBCO thin-film.](http://kreynet.de/wp-content/uploads/2016/01/laserab.jpg)
Oxygen Plasma Treatment
![Barrel chamber for oxygen plasma treatment of YBCO thin-films.](http://kreynet.de/wp-content/uploads/2016/01/barrel.jpg)
Measurement and characterization
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The measurement setup. Multimeter,
- SQUID FLL electronics,
- Temperature controller,
- Waveform generator,
- Oscilloscope,
- FFT signal analyzer,
- Lock-in amplifier,
- Multi purpose data acquisition unit,
- Lead acid battery chargers,
- Battery powered modular SQUID electronics,
- Probe holder,
- Apple Power Macintosh,
- Liquid nitrogen dewar.
All instruments are connected via GPIB Bus to an Apple Power Macintosh (More details).
![FFT analyzer and SQUID FLL electronics.](http://kreynet.de/wp-content/uploads/2016/01/FFTAnalyzer.jpg)