Nano Superconducting QUantum Interference Device sensors for magnetic nanoparticle detection

In this paper, Superconducting QUantum Interference Devices (SQUIDs) based on single layer Nb nanobridge Josephson junctions are described. Devices, with loop area ranging from 4 to 0.5 microm2, have been patterned by Electron Beam Lithography (EBL) in a 20 nm thick Nb layer, achieving a responsivity of about 30 microA/phi0. Magnetization measurements have been performed via switching current measurements at a temperature T = 4.2 K. Preliminary detection of Silica-magnetite (Fe3O4-SiO2) core/shell nanoparticle cluster has been proven.