Preparation And Properties Of BiFeO₃ Based Composite Nanofibers

BiFeO₃ is a typical single-phase multiferroic materials,which show ferroelectric and antiferromagnetic at room temperature simultaneously.Meanwhile,the behavior of magnetoelectric coupling make BiFeO₃ nanomaterials more researcher's appealing in in the field of magnetoelectric sensor,nanoelectronic,high-density data storage media and spintronics,which be attributed to the coexistence of ferroelectric and antiferromagnetic.What's more,BiFeO₃ is a green,pollution-free,non-lead material and has the potential to replace the leaded piezoelectric materials in the current market.The BiFeO₃ material has a lot of advantages,however,this material's application and development be restricted owing to it's larger leakage current and weak ferromagnetism.In summary,we hope to optimize the microstructure and improve the magnetic,ferroelectric and absorption properties of BiFeO₃ by using BiFeO₃ composite other materials.Therefore,BiFeO₃-based composites have great research value and application prospects.In this paper,Bi?NO₃?₂·5H₂O,Zn?NO₃?₂·6H₂O and Fe?NO₃?₃·9H₂O as main materials Pure phase BiFeO₃ fiber and BiFeO₃/ZnFe₂O₄ fiber were fabricated by a sol-gel method combined with an electrospinning technology,respectively.The composition and content of the samples were characterized by FT-IR,XRD and EDS and the micromorphology of the samples was analyzed via SEM and the magnetic,ferroelectric and wave absorbing properties of the samples were tested by VSM,ferroelectric analyzer and vector network analyzer.The conclusions are exhibited as follows:?1?Pure phase BiFeO₃ nanofibers were prepared by sol-gel method combined with electrospinning technology.The results show that the BiFeO₃ precursor fiber has slender and continuous structure.After the annealing temperature of 500?,holding time for 2h and heating rate of 3?/min,BiFeO₃ nanofibers were obtained which have high crystallinity and continuous and slender fiber structure with a diameter of200²50 nm.The grain size of the prepared BiFeO₃ nanofibers is about 32nm.The saturation magnetization is 0.76emu/g,and the remanent polarization is 0.007?C/cm².?2?BiFeO₃/ZnFe₂O₄ composite nanofibers were prepared by sol-gel method combined with electrospinning technology.The results indicated that the diameter of BiFeO₃/ZnFe₂O₄ precursor fibers deformed and shrank after heat treatment process,butthepreparedBiFeO₃/ZnFe₂O₄compositenanofibersstillmaintain one-dimensional fiber structure.Meanwhile,it is found that the nanofibers are composed of smaller perovskite phase BiFeO₃ grains and cubic ZnFe₂O₄ grains.When the calcination temperature is 700?,the saturation magnetization of BiFeO₃/ZnFe₂O₄ composite nanofibers is 3.71emu/g,and the remanent polarization is0.002 C/cm².The wave absorbing property of BiFeO₃/ZnFe₂O₄ composite nanofibers are mainly affected by calcination temperature,two-phase ratio and coating thickness.When the mass ratio is 4:1 and the coating thickness is 3.5mm,the absorption performance of the sample is the best.When the reflection loss of sample less than-10dB,the absorption bandwidth is 5.52GHz and the frequency in the10.24¹5.76GHz range,which can cover part of X band?8.2¹2.4GHz?and the Ku band?12.4¹8GHz?.The reflection loss of the sample reaches the minimum value of-15.7dB at 13.84GHz.