Achievement

We explore alternative methods for metamaterial fabrication based on use of magnetic inclusions, such as magnetic nanoparticles (NP) dispersed in polymer matrices. We predict that microwave permeability of such composites can be tuned from negative to positive values within the range of magnetic resonance. Systems with magnetic NPs of different sizes were fabricated and tested to estimate their potential as building blocks for metamaterials. Magnetic resonance studies were performed in the limits of diluted non-interacting solutions of superparamagnetic NPs in liquid form and high concentrations of particles in solids at different temperatures. We estimate that in dense systems with 5 nm-iron oxide NPs the permeability can be tuned from -0.8 to 2 by the external magnetic field. Such microwave MM can find applications in spintronics, and radio-frequency instrumentation. This study also brings new fundamental knowledge about nanoparticle magnetic dynamics and interparticle interactions.