Lecture at CENAM (15.5.2024)
Wednesday 15.5.2024 at 14:00, Large Lecture room, Centre for Nanotechnology and Advanced Materials
Mikhail Belogolovskii:
Nanoscale magnetic sensing using Josephson junctions
Abstract:
Imaging very small magnetic fields at the nanoscale is a cutting-edge research topic with broad impacts from fundamental physics to new emerging technologies. Superconducting quantum interference devices (SQUIDs) are the current commercial "gold standard" in low-field magnetometry with unprecedented sensitivity and the ability to measure any quantity that can be efficiently converted to magnetic flux. However, downscaling SQUIDs to the 100 nm scale and below has encountered some principal challenges. In the lecture, I discuss the operating principles of the Josephson junction, the heart of superconducting electronic devices, and those of DC SQUIDs, formed by two Josephson junctions connected in parallel to form a closed superconducting circuit. Our original solution to the problems faced by SQUIDs is based on the creation of a single Josephson device with enhanced magnetic field sensitivity, in which the insulating intermediate layer between two superconducting films is replaced with a periodic heterostructure formed by ferromagnetic and normal metal nm-thick films. We believe that such Josephson hybrids are promising platforms for realizing Majorana zero modes.