M.I. Faley, Y.V. Maslennikov, V.P. Koshelets
Measuring systems based on superconducting quantum interferometers (SQUIDs) for nondestructive testing of materials, magnetic microscopy and biomagnetic research were developed. The use of SQUID based on films of high temperature superconductors (HTc SQUID) made it possible to increase the sensitivity while maintaining their operating temperatures from 4.2 K to 77.4 K and a more subtle and less noisy insulation. System for nondestructive testing of materials with thin-film SQUID gradiometer operated stably in the magnetically unshielded space with sensitivity of about 15 fT/cmHz, which was sufficient for detection of magnetic particles measuring about 10 µm at a distance of about 15 mm. Magnetic microscope based on autonomous HTc SQUID with a ferromagnetic antenna has shown the magnetic field sensitivity of about 1 nT/Hz and a spatial resolution of about 1 micron. System for biomagnetic measurements demonstrated sufficient sensitivity for application in magnetocardiography and magnetoencephalography.