Magnesium diboride superconducting quantum interference devices fabricated by focused ion beam

We have recently developed a technique for fabricating Superconductor-Normal-Superconductor (SNS) junctions in MgB₂ thin films using a focused ion beam (FIB). These junctions show a strong modulation of the critical current by applied magnetic field and microwaves. We have made Superconducting Quantum Interference Devices (SQUIDs) with directly coupled pick-up loops using this technique which show large voltage modulations (∼200 μV at 6 K) and a white noise level of 15 μΦ₀Hz^-12/ at 5 kHz. In this work we present the latest results from our devices. We are studying the nature of the barrier created by our fabrication process and also report a preliminary Raman scattering and transport measurement study of resistors made with this technique.