Study On The Performance Control Of BiFeO₃ Based Material And Its Application In Metamaterials

With the development of advanced technologies such as artificial intelligence,quantum communication,and flexible devices,higher requirements are placed on electronic information materials.Metamaterials are widely used in the fields of increasing the directional radiation of antennas,new terahertz devices,space communications,and electromagnetic stealth.BiFeO3 is the only multiferroic material with ferroelectric and antiferromagnetic properties at room temperature.It is urgently needed to further study and improve its performance in order to adapt to China’s manufacturing of 2025,5G communication technology,quantum communication,artificial intelligence,etc.Higher performance indicator requirements.In this dissertation,the solid-state reaction method was used to ion-exchange BiFeO3 and prepare composites.Then,the magnetic media properties were adjusted to make it appear dielectric resonance or magnetic resonance,resulting in negative dielectric constant and negative magnetic permeability.Negative materials are used in the field of electromagnetic metamaterials.Firstly,through the preparation of pure phase BiFeO3,the experimental parameters of the solid phase reaction method were determined,and the thermal behavior of the synthesized BiFeO3 was studied using a thermogravimetric analyzer.The optimal BiFeO3synthesis temperature was 825°C.Bi1-xSmxFe O3 was replaced by Sm³⁺ion instead of Bi³⁺ion.x=0.0-0.05,‘a’increases from 5.5750?to 5.5769?,‘c’decreases from 13.8603to 13.8479?,Ms increased from 0.5039 to 1.2262 emu/g,Hc increased from 87.533 to121.318 Oe,ε?increased from 27 to 46,and tanδranged from 0.034 to 0.011.By replacing the Fe³⁺experimental BiFe1-xVxO3 at the B site with V⁵⁺,the partial crystal phase changes from R3c to Pnma at x=0.09.When x=0.00-0.07,‘a’decreases from 5.5752 to 5.5641?,‘c’increases from 13.8601 to 13.8721?.when x=0.09,‘a’of the R3c structure is 5.5615?,‘c’is 13.8782?,‘a’of the Pnma structure is 5.5698?,‘b’is 7.9904?,and‘c’is5.5673?.The ratio of R3c structure in x=0.09 grains is about 86.7%,Pnma is about13.3%.The increase in small grains and pores was observed in the microscopic morphology,but larger cuboids and finer grains appeared at x=0.09.x=0.00-0.09,Ms increases from 0.5036 to 1.2061 emu/g;Hc increases from 87.624 to 98.383 Oe;ε’increases from 25 to 41,and tanδranges from 0.012 to 0.026.Secondly,the experimental study on the co-substitution of single-ion Y³⁺and multi-ion Y-Ba-Co was compared.Y³⁺replaces the experiment Bi1-xYxFeO3,the crystal phase does not change,the grain size tends to be uniform,and there is no fixed shape and orientation.x=0.02-0.08,Ms increases from 0.1225 to 1.9941 emu/g;?’increases from 24to 41,and tanδranges from 0.004 to 0.007.Y-Ba-Co co-substitution experiment Bi0.7Y0.2Ba0.1Fe0.98-xCoxO3,the crystal phase shows samples are all P4mm tetragonal phase.x=0.01-0.06,‘a’decreases from 5.5682 to 5.5635?,‘c’decreases from 6.9475 to6.9253?,and increases to 6.9352?;Ms increases from 7.81 to 9.68 emu/g;Hc increases from 110.66 to 166.68 Oe;ε’increases from 34.19 to 56.26.Then,the magnetic resonance or dielectric resonance that occurred on the material was replaced by Li⁺and Ba-Cr.Li⁺replaces experimental Bi1-xLixFeO3,theμ?magnetic resonance phenomenon occurs at 2.5-3.0 GHz,which produces negative magnetic permeability.The Ba-Cr co-substitution experiment Bi0.9Ba0.1Fe1-xCrxO3,the dielectric resonance behavior occurs in the sample at 0.7-0.9 GHz generates a negative permittivity.The negative dielectric constant generated by dielectric resonance can make the material used as an electro-negative material in the field of electromagnetic metamaterials.Finally,the magnetic media properties of BiFeO3 matrix composites were studied.In the experiment of BiFeO3-Bi2Fe4O9 composites was used to design a new type of composite material by using this kind of impurity phase.Micromorphology and EDS analysis determine the grain characteristics of the two-phase material.The sample undergoes dielectric resonance behavior at 1-1.2 GHz,creating a negative dielectric constant.Using the equivalent circuit model analysis method,the macroscopic properties of the material are equivalent to the LRC series circuit,and the dielectric resonance behavior is described.BiFeO3-BaFe12O19 composites（1-x）BiFeO3-xBaFe12O19.x=0.03,0.05,0.07 and 0.09 wt%,Ms increased from 0.07 to 0.7 emu/g;Hc increased from 160 to3150 Oe;ε?was 40,46,53 and 62;tanδwas 0.02,0.04,0.06 and 0.10.