Vortex Trapping in Hybrid Magnetometers

TL;DR

This paper investigates vortex trapping in hybrid superconducting magnetometers, develops a new theoretical model for vortex behavior, and demonstrates improved sensor performance through experimental validation.

Contribution

A new model for vortex trapping in superconductors is derived and experimentally validated, enhancing understanding and design of hybrid magnetometers.

Findings

Good agreement between theory and experiment on vortex densities

Achieved field gain up to G=7 in hybrid magnetometers

Effective measurement range of 175 microtesla

Abstract

Hybrid magnetometers based on a normal conducting sensor and a superconducting flux concentrator have been investigated. When this sensor is operated in an unshielded environment flux vortices can be trapped in the superconducting body when the sensor is cooled. Thermal hopping of the trapped vortices gives rise to 1/f noise. The mechanism for vortex trapping has been investigated. A new model for the critical field for vortex trapping and vortex densities has been derived. Experimental verification on YBa2Cu3O7-delta (YBCO) strips with a Scanning SQUID Microscope shows very good agreement between measurements and the new theory. The results have been applied in a hybrid magnetometer design based on a bismuth Hall sensor and an YBCO flux concentrator. Measurements show a field gain up to G=7 with a large effective range of 175uT.