Optimal microwave absorption of hierarchical cobalt dendrites enhanced by multiple dielectric and magnetic resonance

In this paper, we reported the microwave performance of three-dimensional hierarchical cobalt dendrites dispersed in the paraffin matrix (70 wt. %) in the frequency range of 2–18 GHz. The cobalt dendrites presented multiple dielectric relaxation and magnetic resonances, contributing to broaden the microwave absorption bandwidth. The calculated reflection loss shows that the cobalt dendrites have optimal microwave absorption. The maximum reflection loss reaches −58.60 dB at 13.75 GHz with a matching thickness of 1.4 mm. Meanwhile, an effective absorption bandwidth of 5.03 GHz from 11.34 to 16.37 GHz was obtained, possessing a better microwave absorption than earlier reported materials. The cobalt dendrites have potential application as candidate for microwave absorption.