Sr0.8Re0.2Fe11.8Co0.2O19(Re=La,Nd)的制备、表征及吸波性能

采用溶胶凝胶法,制备Sr0.8Re0.2Fe11.8Co0.2O19(Re=La,Nd)复合铁氧体。采用X射线衍射仪、扫描电子显微镜、振动样品磁强计和矢量网络分析仪表征粉体的结构及电磁性能。结果表明:得到的粉体为纯净的磁铅石型铁氧体,La3+掺杂样品的各项性能明显改善。在室温条件下,稀土离子掺杂后样品的Ms受到稀土离子掺杂的影响较小,Hc则明显提高;La^3+掺杂样品和Nd3+掺杂样品的Ms值接近,前者的Hc值则明显强于后者的,Sr0.8La0.2Fe11.8Co0.2O19的Ms和Hc分别为58.08A m^2/kg和362.0kA/m。稀土离子掺杂使铁氧体样品的复介电常数(ε′和ε″)增大,与Nd3+掺杂样品相比,La3+掺杂样品的介电损耗和磁损耗改善更为明显。利用传输线理论优化设计时发现,在1.2~2.4 mm之间,随着厚度的增加,Sr0.8La0.2Fe11.8Co0.2O19的反射率峰值先减少后增加,逐渐向低频移动;在厚度为2.0 mm时,其反射率峰值达到最小值为27.8 dB(11.8 GHz),小于10 dB的吸波带宽为5.2 GHz(9.5~14.7 GHz)。

Preparation,characterization and absorption properties of Sr0.8Re0.2Fe11.8Co0.2O19(Re=La,Nd)

Sr0.8Re0.2Fe11.8Co0.2O19(Re=La,Nd)composite ferrites were prepared by sol-gel method.The structure and electromagnetic properties of the powders were characterized by X-ray diffractometry,scanning electron microscopy,vibration sample magnetometer and vector network analyzer.The results show that the powders are pure lead-magnetite ferrite,and the properties of the samples doped with La^3+are improved more obviously.At room temperature,the Hc of the samples doped with rare earth ions increase to a certain extent,while the Ms values of the samples doped with La^3+and Nd^3+are similar,while the Hc value of the sample doped with La^3+is significantly stronger than that of the sample doped with Nd^3+.Ms and Hc of Sr0.8La0.2Fe11.8Co0.2O19 are 58.08 A m^2/kg and 362.0 kA/m.The complex permittivity of ferrite samples increases with rare earth ions doping.It can be seen that the dielectric loss and magnetic loss of the sample doped with La^3+are improved more obviously.The peak reflectivity of Sr0.8La0.2Fe11.8Co0.2O19 first decreases and then increases with the increase of thickness between 1.2 mm and 2.4 mm,and gradually moves to low frequency.When the thickness is 2.0 mm,the minimum value of the peak reflectivity of Sr0.8La0.2Fe11.8Co0.2O19 is 27.8 dB(11.8 GHz),and the absorbing bandwidth that less than 10 dB is 5.2 GHz(9.514.7 GHz).