Simultaneous epsilon-negative and mu-negative property of Ni/CaCu3Ti4O12 metacomposites at radio-frequency region

Abstract

Metacomposites with simultaneous epsilon-negative and mu-negative property have drawn tremendous attentions due to their promising applications in electromagnetic field. Herein, Ni/CaCu3Ti4O12 (Ni/CCTO) metacomposites were prepared by low-temperature pressureless sintering method. It was observed that Ni chains were gradually interconnecting to each other with increasing Ni content, and a percolation behavior was observed. Epsilon-negative property was obtained above percolation threshold attributing to the synergistic effect of induced electric dipole and low-frequency plasma oscillation in Ni networks, which was explained by the superposition of Drude and Lorentz model. Mu-negative property was observed above ∼34 MHz and ∼120 MHz for 60 wt% and 70 wt% Ni/CCTO composites respectively, which may originate from the combined effects of diamagnetic response, domain wall motion and gyromagnetic spin rotation. Hence, simultaneous epsilon-negative and mu-negative property at radio-frequency region was realized in Ni/CCTO metacomposites. Besides, the composites presented hopping conduction behavior, and then changed into metal-like conduction behavior with increasing Ni content. The impedance response of Ni/CCTO composites clarified the correlation between epsilon-negative and inductive character. This work could broaden the scope of metacomposites and pave its way to potential applications of electromagnetic shielding, novel antenna, and high-k capacitors.