Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

In the present article, experimental results regarding fully integrated superconducting quantum interference devices (SQUID), including a circuit to tune and optimize the main sensor device characteristics, are reported. We show the possibility of modifying the critical current of a SQUID magnetometer in liquid helium by means of a suitable heating circuit. This allows us to improve the characteristics of the SQUID sensor and in particular to optimize the voltage-magnetic flux characteristic and the relative transfer factor (responsivity) and consequently to also improve the flux and magnetic field noise. It is also possible to reset the SQUID sensor in case of entrapment of magnetic flux, avoiding taking it out of the helium bath. These results are very useful in view of most SQUID applications such as those requiring large multichannel systems in which it is desirable to optimize and eventually reset the magnetic sensors in a simple and effective way.

Automated summary

In this article, experimental results are presented on fully integrated superconducting quantum interference devices (SQUID), which include a circuit for tuning and optimizing the main sensor device characteristics. It is shown that the critical current of a SQUID magnetometer in liquid helium can be modified using a suitable heating circuit. This allows for the improvement of SQUID sensor characteristics, such as the voltage-magnetic flux characteristic, responsivity, as well as flux and magnetic field noise. Additionally, the SQUID sensor can be reset in case of magnetic flux entrapment without removing it from the helium bath. These findings are valuable for optimizing and resetting magnetic sensors in large multichannel systems.