Fabrication of DC-SQUID using an as-grown MgB₂ Film

Abstract

We have developed DC-SQUID using an as-grown MgB₂ film for devices detecting magnetocardiogram (MCG) and other purposes. Our as-grown MgB₂ film was fabricated by a low-temperature co-evaporation method on a c-plane sapphire substrate using a molecular beam epitaxy (MBE) apparatus. A nano-bridge DC-SQUID was fabricated using a standard lithography technique with a focused ion beam (FIB) apparatus. The modulation voltage is in the range of 10 μV and 100 μV, dependent on temperature. We have successfully detected the MCG signals.