Development and Characterization of Magnetoelectric Nanocomposites and Thin-Film Laminates for Biosensor Applications

Magnetoelectric (ME) effect has a number of promising applications in sensors, energy harvesting, antennas, drug delivery, etc. In ME materials the electric polarization can be controlled by varying the material’s magnetization state and, conversely, varying the electric polarization affects the material’s magnetization state. The ME effect has been observed in a few single-phase multiferroic materials; however, the effect is relatively weak at room temperature, which hampers useful applications. More robust ME behavior has been achieved in composites that combine mechanical coupled magnetostrictive and piezoelectric materials arranged in a matrix. These composites can be produced in versatile connectivity configurations/matrices with a wide choice of materials, volume fraction, and microstructure and can exhibit several orders of magnitude stronger ME effect than single-phase ME materials. In this work, the development and characterization of two different types of multi- phase ME materials, nanocomposites, and thin-film laminates are investigated. Mag- netoelectric composites of CoFe2O4-BaTiO3 are synthesized using commercially avail- able CoFe2O4 and BaTiO3 precursors with employing the inexpensive and scalable process based on ball-milling and high-temperature sintering/annealing for drug de- livery applications. ME thin film laminates of AlN and FeGaZr also are developed and utilized as the building block for fabrication of a suspended ME sensor for integration into a magnetic field sensor.