Communication-A Weakly Negative Permittivity of Carbonyl Iron and La-Doped Barium Ferrite Composites at Radio Frequency

Percolative composites with negative permittivity have attracted much attention. For carbonyl iron and La-doped barium ferrite composites, the conduction mechanism changed from hopping conduction to metal-like conduction when carbonyl iron content increased. When carbonyl iron content was 80 wt%, which exceeded but approached the percolation threshold, a weak value of negative permittivity between -200 and 0 was achieved. In addition, the analysis of reactance revealed that inductance characteristic resulted in the negative permittivity. This work provides a way to design the metal composites with a weakly negative permittivity to apply in different fields.

Automated summary

This study investigates the percolative composites with negative permittivity, focusing on the change in conduction mechanism and the occurrence of weakly negative permittivity as the carbonyl iron content increases. It is found that inductance characteristic plays a role in the negative permittivity observed in the composites. These findings offer a potential way to design metal composites with weakly negative permittivity for various applications.