Magnetic properties of Ni0.4Zn0.6Fe2O4 synthesized by the polyol method and its epoxy composites

Ni_0.4Zn_0.6Fe₂O₄ powders were prepared via a polyol method with diethylene glycol (DEG) as reaction medium. After synthesis, the particles were characterized by the X-ray diffraction (XRD), the thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectrophotometer and vibrating sample magnetometer (VSM). The XRD curve indicates that the ferrite has smaller grain size (~5 nm) and typical spinel structure. The TGA and FT-IR results confirm the polyol molecules are adsorbed on the surface of the ferrites. The VSM result shows that the ferrite has superior saturation magnetization (-58.29 emu/g) and minor remnant magnetization (2.52 emu/g). Then, the magnetic epoxy composites were fabricated by mixing this ferrite and epoxy resin in acetone and using tetraethylene pentamine (TEPA) as a hardener. The complex permeability (μ\´, μ") in the frequency of rang from 10 MHz to 1 GHz of this composites were studied by an impedance analyser (Agilent E 4991A). The measure results reveal that the real part (μ\´) are rising from 1.06 to 1.89 at a frequency of 100MHz with the mass fraction of the ferrite in the composite increasing from 10%-65%, and the imaginary part (μ") rising from 0.006 to 0.221, while magnetic loss tangent (tan5) rise from 0.005 to 0.117.