The Study On Silicate Medium And Spinel Ferrite Composites Based Magnetic-dielectric Materials

Magnetic-dielectric materials have widely application prospects in the development of miniaturization and multifunction on electronic devices,for example,antennas,filters and electromagnetic interference device.Ferrites have not only good magnetic properties,but also high resistivity,low eddy current loss and very good thermochemical stability and other excellent properties.In order to solve the problem of miniaturization of electronic equipment,this paper mainly study on silicate medium and spinel ferrite composites based magnetic-dielectric materials?1-x?Mg₂SiO₄-xLiFe₅O₈,?1-x?Li₂MgSiO₄-xLiFe₅O₈ and?1-x?Li₂MgSiO₄-xMgFe₂O₄ were prepared by solid-state reaction method.The related research about these three new systems of magnetic dielectric materials has not been publicly reported,and this paper studied their phase,dielectric properties and magnetic properties.It was found that the materials of the three systems have some common characteristics:they all have the soft magnetic properties,with the increase of ferrite content,the saturation magnetization,magnetic permeability and magnetic loss of the materials increased,and the permeability increased with increase of the sintering temperature.There are only Mg₂SiO₄ and LiFe₅O₈ in the?1-x?Mg₂SiO₄-xLiFe₅O₈magnetic-dielectric material.When the content of LiFe₅O₈ is below 20 wt%,the dielectric constant of the material is around 20,the dielectric loss is less than 0.5.The dielectric constant and dielectric loss increase as long as the content of LiFe₅O₈ increases.The saturation magnetization is 15.98 emu/g with the content of LiFe₅O₈ is 40 wt%.The material's magnetic loss is less than 0.45 when the frequency is from 10MHz to 1GHz.When the content of LiFe₅O₈ is 10wt%or 15wt%,a small amount of Mg₂SiO₄ can be found in the?1-x?Li₂MgSiO₄-xLiFe₅O₈ magnetic-dielectric material.Under the condition that x is 15wt%,sintering temperature is 1075^oC and frequency is from 15kHz to 9MHz,the dielectric constant of the composites is from 14.9 to 14.7 and the dielectric loss is in the range of 9×10^-3-3×10^-3.In general,the dielectric constant increases with the increasing content of LiFe₅O₈.The dielectric loss decreases in the process of x varies from 10%to 15%and then increases.The saturation magnetization is 16.83 emu/g as the content of LiFe₅O₈ is40 wt%.The material's magnetic loss is less than 0.45 when the frequency is from 10MHz to 1GHz.