Synthesis, characterization and microwave absorption properties of Fe3O4/Co core/shell-type nanoparticles

Co coated Fe3O4 core/shell-type nanoparticles were fabricated by hydrothermal technique and electroless plating process. X-ray powder diffraction (XRD), X-ray fluorescence spectrometer (XRF) and transmission electron microscope (TEM) were employed to investigate the crystal structure, element composition and morphology of the prepared nanoparticles. Vibrating sample magnetometer (VSM) and vector network analyzer were used to measure the magnetic properties and electromagnetic parameters of pure Fe3O4 and Fe3O4/Co core/shell-type nanoparticles, then reflection losses (RL(dB)) were calculated in the frequency range of 2–18 GHz. Magnetic studies revealed typical ferromagnetic behavior for the pure Fe3O4 and Fe3O4/Co core/shell-type nanoparticles with their saturation magnetization (Ms = 63.1 and 72.4 emu/g) and coercivity (Hc = 99.5, and 165.4 Oe), respectively. Due to the existence of the core/shell structure, the electromagnetic characteristic of the Fe3O4/Co nanoparticles exhibit better microwave absorption performance than the pure Fe3O4 in the range of 2–18 GHz, such as more powerful absorbing property and wider frequency band of microwave absorption.

Graphical abstractThe Fe3O4/Co core/shell-type nanoparticles are fabricated by hydrothermal technique and electroless plating process. TEM shows that the particle has core/shell structure with a clearly distinguishable interface, containing Fe3O4 nanoparticle as core and Co as shell. The outer cobalt nanoshell is mainly uniform around 63 nm in thickness and Fe3O4 nanoparticle is encapsulated completely. Moreover, the nanoparticles exhibit strong electromagnetic absorption properties and could be a nice candidate for being a highly efficient microwave absorbent.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The Fe3O4/Co core/shell nanoparticles are firstly fabricated. ► The detailed analysis of phase formation is discussed. ► The electromagnetic absorption property is defined. ► The effect of core/shell structure is considered for the good microwave absorption.