Detecting the Total Stray Fields of Ferrogel Nanoparticles Using a Prototype Magnetoimpedance Sensor: Modeling and Experiment

A prototype biosensor operating on the basis of the giant magnetoimpedance effect (GMI) with a [Cu/FeNi]5/Cu/[FeNi/Cu]5 multilayer sensing element is developed to study ferrogels. The GMI is measured in the initial state and in the presence of ferrogels with different concentrations of superparamagnetic nanoparticles, allowing the stray fields of ensembles of magnetic nanoparticles in ferrogels to be characterized. The description produced using the proposed electrodynamic model agrees satisfactorily with the GMI experimental data obtained for a ferrogel-coated film element.