Dielectric Properties Of BST/BNFO Gradient Multiferroic Ceramics

Multiferrioc material is a kind of multifunctional material that posse sses both magnetic and electric properties.Material of the same phase consis ts oftwo or two more properties of iron and exibit electromagnetic co upling effect.Ferroelectric and ferromagnetic in some cases is difficult tocoexist.Even if some materials possess both ferroelectric and magnetic at room t emperature,but itsinterior electromagnetic coupling effect is low.To some exte nt this limit its practical application.Graded material is an advanced co mposite material by continuous(or quasi-continuous)change the structures,compo siton and other factors of the two materials.Thus can make its performanc e corresponding to the changeof compositon and huge potentia structure.Gr aded materials’ compositon,microstructure(ceramic,metal,etc.is not only a contin uos distribution but also canbe controlled.Special graded structure and compositi on can produce electromagnetic couplin effect,it offers a huge potential pra ctical application in energy storage devices,sensor and memory devices.The BST/BNFO was prepared by a conventional solid-state reaction proc ess.Then graded ceramics can be sintered according to different graded ratio an d way.Its perovskite structure,microstructure,ferroelectric,magnetic and dielectr ic properties were characterized by X-ray diffraction,scanning electron microsc opy,P-E loop tracer,Vibrating Sample Magnetometer and Automatic Componen t Analyzer.The BST/BNFO ceramic materials were prepared by solid-state rea ction process.Graded ceramics can be sintered according to its different graded ratio and way.The perovskite structure,microstructure,ferroelectric,magnetic a nd dielectric properties of ceramic materials and graded materials were characte rized by X-ray diffraction,scanning electron microscopy,P-E loop tracer,Vib rating Sample Magnetometer and Automatic Component Analyzer.We discusse d its ferroelectric and magnetic properties.Moreover,its electromagnetic coulplin g effect can be analyzedThis process has resulted into multiferrioc properties at room temperature and large electromagnetic coupling effect have been obtained in PZT/BFO gra ded system.The dielectric constant change reached 10% for left and right grade d ceramics under magnetic field.The BST/BNFO ceramic materials exhibited both electric and magnetic properties at room temperature,whose magnetic prop erty in direct proportion to BNFO.The dielectric constant change reached 6% for graded ceramics under magnetic field.The research indicated that electroma gnetic coupling effect is not directly proportional to magnetism which resulted from its larger component differences.The related mechanism was discussed wit h respect to diffusion behavior and moredefects in the graded material.These c omposites with large dielectric constant changecan find application in energy st orage devices,sensor and memory devices.