Synthesis of hierarchical sword-like cobalt particles and their microwave absorption properties

In this paper, we reported synthesis of the cobalt particles with a hierarchical sword-like structure through a liquid reduction method. We have investigated the electromagnetic properties of the cobalt particles in the microwave frequency range of 2-18 GHz. The cobalt particles presented multiple dielectric and magnetic resonance peaks, which are related to their unique structure. We have predicted the microwave absorption properties of the cobalt particles according to the transmit line theory. The maximum reflection loss (RL) of the cobalt particles reaches -60.13 dB, and the effective absorption bandwidth (RL ≤ -10 dB) is 5.42 GHz corresponding to a thickness of 1.4 mm, revealing better microwave absorption than previously reported materials. The superior microwave absorption properties indicate that the as-prepared cobalt particles have potential application as candidates for microwave absorption.