Radio-frequency epsilon-negative property and diamagnetic response of percolative Ag/CCTO metacomposites

Abstract

Here, Ag/CaCu3Ti4O12 (Ag/CCTO) percolative nanocomposites were fabricated by an in-situ synthesis, where the percolation-related transitions of dielectric and magnetic properties were investigated at radio-frequency band. Epsilon-negative property (ε′ < 0) and diamagnetic responses (μ′ < 1) were observed in percolated composites, owing to low-frequency plasmonic state and induced eddy currents within formed conductive Ag networks respectively. The competitive effect between polarization response of ε′-positive CCTO matrix and collective plasma oscillation of ε′-negative Ag networks leads to the tunable negative permittivity. The clarification of inductive character of ε′-negative materials benefits constructing effective strategy for adjusting negative value of dielectric constant.