Application of Magnonic Crystals in Magnetic Bead Detection

This paper aims at studying a sensor concept for possible integration in magnetic field-based lab-on-chip devices that exploit ferromagnetic resonance (FMR) phenomena in magnonic crystals. The focus is on 2D magnetic antidot arrays, i.e., magnetic thin films with periodic non-magnetic inclusions (holes), recently proposed as magnetic field sensor elements operating in the gigahertz (GHz) range. The sensing mechanism is here demonstrated for magnetic nano/microbeads adsorbed on the surface of permalloy (Ni80Fe20) antidot arrays with a rhomboid lattice structure and variable hole size. Through extensive micromagnetic modelling analysis, it is shown that the antidot arrays can be used as both bead traps and high-sensitivity detectors, with performance that can be tuned as a function of bead size and magnetic moment. A key parameter for the detection mechanism is the antidot array hole size, which affects the FMR frequency shifts associated with the interaction between the magnetization configuration in the nanostructured film and the bead stray field. Possible applications of the proposed device concept include magnetic immunoassays, using magnetic nano/microbeads as probes for biomarker detection, and biomaterial manipulation.

Automated summary

This paper studies a sensor concept for potential integration in magnetic field-based lab-on-chip devices that utilize ferromagnetic resonance (FMR) phenomena in magnonic crystals. The focus is on 2D magnetic antidot arrays, which are magnetic thin films with periodic non-magnetic inclusions, proposed as magnetic field sensor elements in the gigahertz (GHz) range. Through micromagnetic modeling analysis, it is demonstrated that the antidot arrays can function as both bead traps and high-sensitivity detectors, with adjustable performance based on bead size and magnetic moment. The hole size in the antidot array is a key parameter for the detection mechanism, affecting the FMR frequency shifts caused by the interaction between the magnetization configuration in the nanostructured film and the bead stray field. Potential applications of this device concept include magnetic immunoassays and biomaterial manipulation.