Modelling of thin film magnetoimpedance sensitive element designed for biodetection

Abstract

Magnetic soft matter (ferrofluids or ferrogels) is one of the rapidly growing areas of research and applications including magnetic biosensing. Giant magnetoimpedance is the effect with proven capacity to magnetic label detection. In this work, we describe a universal model to simulate conditions of magnetic biodetection and to check its validity with giant magnetoimpedance sensitive element based on magnetic multilayer. Finite element method allows calculations of high-frequency current distribution using the Maxwell's equations taking into account the magnetodynamics of iron oxide water-based ferrofluid in small channels similar to the blood vessels. The modelling was realized with the licensed software Comsol ©. The calculations were performed on a specialized engineering server based on four processors Intel Xeon E5 and 124 Gb RAM, adapted for parallel computations and suitable for description of individual layers with nanometer dimensions for the number of elements in the mesh structure above 106 cells. The designed model allows calculations of the current density, the outside magnetic flux, resistivity, etc. for each one of the created cells and total values by integration of sub-domains. One can quantitatively describe concentration of ferrofluid, velocity and pressure in the blood vessel. These changes affecting on the giant magnetoimpedance of the FeNi-based multilayer were both calculated and measured. © 2018 The Authors, published by EDP Sciences.