Magnetic field-assisted drop casting of Gr/Magnetic materials: enhanced uniformity for magnetic field sensor application

Drop casting method is a widely used technique in various fields of science and technology due to its ultra-fast, cost-effective, and straightforward nature. However, its application for coating materials containing magnetic elements is limited because of the agglomeration of materials during the coating process. In this study, we achieve uniform layers by applying heat and a magnetic field during the coating procedure, conditions that would otherwise be unattainable. The heat and magnetic fields are generated by passing electrical current through the substrate. We apply our developed technique to coat the graphene-magnetic nanoparticle composite on the surface of a magnetic field sensor, which is highly sensitive to surface roughness. As a result, we observe an enhanced Giant Magnetoimpedance (GMI) ratio, increasing from 280 to 361%. No enhancement is noted for samples coated without applying current to the sensor, as the coated layer lacks smoothness. Our findings represent a significant advancement in the drop casting technique, with potential applications for a wide range of composite materials containing magnetic elements.