Preparation And Microwave Absorption Properties Of Multiferroic Fe(C)/BFO Nanocapsules

BFO is one of several rare single-phase multiferroic materials that are bothferroelectric and weakly ferromagnetic at room temperature. The ferroelectric polarizationof BFO can cause the dielectric loss and the ferromagnetic polarization of BFO can causethe magnetic loss. It has great application potential in the field of wave absorptionmaterials. However，single phase BFO’s wave absorption properties and its application arelimited for its having weak ferromagnetic and large leakage current in bulk phase.Based on the above reasons，combining the single-phase BFO with ferromagneticα-Fe particles into absorption materials with the multiferroic composite nanocapsulestructure are designed in this paper. Taking advantage of BFO dielectric dispersioncharacteristics can regulate the dielectric dispersion characteristics of magneticnanocapsules and the absorption properties in different band (especially the S band and Lband)，broaden absorption band，and improve the absorption properties of nanocapsule.Two kind methods are chose to prepare the multiferroic composite nanocapsule. Theresearch results show，the core of the samples prepared by DC plasma arc is Fe, and theshell are BiFeO3and Bi2Fe4O9, the core of the samples prepared by hydrothermal methodand DC arc method is Fe, and the interface layer is C as well as the shell is single-phaseBFO, forming a double shell structure nanocapsules. Microwave absorbing properties ofthe results show, for the samples prepared by DC plasma arc, the reflection coefficient isbetween-15dB to-19.3dB, with the thickness of2mm-7mm and the range from3GHz to11GHz. The maximum peak of the reflection coefficient is-19.3dB appearing at10.5GHz,with the thickness of2mm. For the samples prepared by hydrothermal method and DC arcmethod, the reflection coefficient is between-20dB to-39dB, with the thickness of1.2-8mm and the range from2GHz to13.5GHz. The maximum peak of the reflectioncoefficient is-39dB appearing at11.3GHz, with the thickness of1.6mm. The experimental results show, when the frequency of electromagnetic wave in therange of2-18GHz, the absorbing property of Fe (C)/BFO is better than that of Fe/BFO. Inthe low frequency range of2-3GHz, the Fe (C)/BFO has the absorption coefficients of lessthan-10dB, and has good wave absorbing properties at low frequency. The Fe(C)/BFOdouble shell nanocapsule structure prepared by hydrothermal method and DC arc methodhas realized the frequency control for Fe (C) parameter with the single-phase BFO, greatlyimproved the dielectric loss and magnetic loss through variety materials electromagneticcoupling in nano level. The Fe (C)/BFO has excellent wave absorbing properties.