Studying on Ag Nanorods Embedded in Dielectric as Future Negative Index Metamaterials

A heterogeneous medium consisting of randomly oriented silver nanorods embedded in Co0.05Ti0.95O2 (CTO) matrix was prepared using the sol- gel method. In this work, negative permittivity properties and magnetic behavior of composites with different content of Ag nanorods embedded in Co0.05Ti0.95O2 matrix are investigated. The structure and morphology characterizations of Ag/CTO nanocomposites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The permittivity and permeability behaviors of samples were investigated. It is shown that with increasing of Ag content (~35%) the composite shows negative values for permittivity which is called electrically negative metamaterial. The silver networks possess diamagnetic behavior due to Eddy current that combine with the magnetic behavior of Co0.05Ti0.95O2 matrix. The permeability spectra of composites reveal that the permeability of these samples decreases continuously with the increasing of frequency. Additionally, the permeability spectra shows negative susceptibility in sample with high Ag content (35%) at high frequency.