锂镧铁氧体/PANI纳米复合材料的磁性质和吸波性能

Magnetic and Microwave Absorption Properties of Lithium-lanthanum Ferrite and PANI Nano-Composites

利用溶胶-凝胶自蔓延燃烧方法分别制备LiFe5O8和LiLa0.03Fe4.97O8铁氧体纳米粉末,采用化学方法合成十二烷基苯磺酸钠(LAS)与盐酸(HCl)混合掺杂的聚苯胺(PANI)粉末,利用高能球磨法制备铁氧体与聚苯胺纳米复合材料,用XRD、VSM及微波矢量网络分析仪对样品进行表征。结果表明,球磨后LiLa0.03Fe4.97O8/PANI复合材料的衍射峰位有一微小偏移,与其晶格膨胀有关。复合材料的比饱和磁化强度下降,而矫顽力增加。与单纯的铁氧体纳米材料相比,复合材料的阻抗匹配特性得到改善,其介电损耗和磁损耗均有提高,磁共振损耗明显增加,但LiLa0.03Fe4.97O8/PANI复合材料的吸波性能逊于LiFe5O8/PANI。

LiFe_5O_8 and LiLa_（0.03）Fe_（4.97）O_8 ferrite nanopowders were prepared by sol-gel self-propagating combustion method,and polyaniline（PANI） doped with a mixture of sodium dodecylbenes ulfonate and hydrochloric acid（LAS-HCl）was synthesized by chemical method.Ferrite-PANI nano-composites were prepared by high energy ball milling using powders of ferrite and PANI as raw materials.All the samples were characterized by X-ray diffractometry（XRD）,vibrating sample magnetometry（VSM） and vector network analyzer.The results show that the diffraction peaks of LiLa_（0.03）Fe_（4.97）O_8-PANI composites after milling have slight shifts due to lattice expansion.The specific saturation magnetization of the composites decreases,while the coercivity increases.Compared with pure nanoferrites,the good impedance matching characteristics of the composites improved their dielectric loss and magnetic loss,and magnetic resonance loss increases significantly,but the microwave absorbing performance of LiLa_（0.03）Fe_（4.97）O_8/PANI is inferior to that of LiFe_5O_8/PANI.