The architecture assembled from Ni nanocones and its microwave-absorbing properties

Spherical or branch-like architectures assembled from Ni nanocones have been synthesized. Micromagnetic simulation of a single Ni nanocone reveals that it has a unique magnetization structure with a vortex structure at the bottom and a uniform structure at the top. Two resonance peaks at 4.4 and 12.0 GHz appear in the high-frequency magnetic spectrum. The complex permittivity is very low in the frequency range 1-18 GHz, which makes the magnetic permeability and the permittivity match well and benefits the microwave absorption.