Preparation and magnetic properties of Fe_2O_3 microtubules prepared by sol-gel template method

摘要

Fe(OH)3 precursor sol was prepared by a sol-gel method.The precursor sol was dipped onto the absorbent cotton,and gel was formed on the absorbent cotton template after the volatilization of moisture.Fe2O3 microtubules were synthesized after the process of self-propagation or calcination.The phase,morphology,and particle diameter of the samples were examined by X-ray diffraction(XRD) and scanning electron microscopy(SEM),and the magnetic properties of the samples were measured using a vibrating sample magnetometer(VSM).The external diameters of Fe2O3 microtubules ranged between 8 and 13 μm,and the wall thicknesses ranged between 0.5 and 2 μm.The type of the calcination method plays a significant role in developing the Fe2O3 phase and the variation in the magnetic properties in the sol-gel template complexing method.γ-Fe2O3 was synthesized by a self-propagation method.However,α-Fe2O3 was synthesized after calcination at 400 °C for 2 h.The coercivity of the samples synthesized by calcination at 400°C for 2 h after self-propagation was found to increase significantly,thereby presenting hard magnetic properties.