镍铁氧体纳米晶的制备及电磁性能研究

Preparation of Nanocrystalline Nickel Ferrite and Its Electromagnetic Properties

通过高分子凝胶法制备了尖晶石型镍铁氧体（NiFe2O4）纳米晶.采用FT-IR,X射线,TEM和波导等方法对产物以及产物的电磁性能进行了表征.结果表明,干凝胶为无定型状态,当煅烧温度高于400 ℃时,形成纯相的尖晶石型纳米晶.煅烧温度为400,600和800 ℃时,由透射电镜照片可知粉体平均粒径分别约为8,25和40 nm,红外光谱显示金属-氧离子（M-O）键的特征吸收峰出现了红移,该峰红移23 cm^-1;纳米晶在8～12 GHz的测试频率范围内具有介电损耗与磁损耗,随着热处理温度的升高,镍铁氧体纳米晶的介电损耗和磁损耗明显增大.

Nanocrystalline nickel ferrite was prepared by polyacrylamide gel, taking acrylamide as monomer and N, N-methylenediacrylamide as lattice agent. FT-IR spectrometer, XRD, TEM and waveguide were used to characterize the gel, products and their electromagnetic properties after calcining. XRD patterns showed that the dried gel is amorphous, the spinel nickel ferrite formed at not lower than 400 ℃, The grain sizes and M-O characteristic absorption bonds are dependant on heat treatment temperature. When the calcining temperatures are 400, 600 and 800 ℃, the grain sizes are 8, 25 and 40 nm, respectively, as identified by TEM. The FT-IR spectra illustrated that the M-O characteristic absorption bonds shift from 590 cm^-1 to 613 cm^-1. The nanocrystalline presents not only dielectric loss but magnetic loss in the frequency range of measurement, and both the losses of spinel-type nanocrystalline increases obviously with increasing heat treatment temperature.