Investigation On The Preparation Process And Properties In Ba-doped BiFeO₃ Materials

The development trendency of miniaturization device makes many researchers have a great interest to study new multiferroic materials,which possess many functional properties.Multiferroic BiFeO3 may be a unique material that shows both ferroelectric and ferromagnetic properties at room temperature.As for BiFeO3 bulk ceramics,it is very difficult to synthesis pure BiFeO3 bulk ceramics.As a result,it is largely difficult to study the ferroelectric,ferromagnetic,and magnetoelectric effect in BiFeO3.On the other hand,the photovoltaic effect in ferroelectric materials has been as a new research field in recent years.Our research work focused on single phase BiFeO3 system.Ba-doping was proved to be beneficial to enhancing the magnetization of the samples.Furthermore,the properties about electric-field modulation of magnetism in Bi0.95Ba0.05FeO3 at room temperature have been well investigated in this article.The high quality and pure phase of Bi0.95Ba0.05FeO3 film were prepared by PLD.And the magnetic properties and photovoltaic properties of the Bi0.95Ba0.05FeO3 thin film have also been studied.In detail,the structure and morphology characteristics of the samples were investigated by XRD,SEM,XPS,Raman and so on.The magnetic properties were tested through the VSM.And photovoltaic properties were investigated by Keithley2400.The main work and results in this article are listed as following.First,multiferroic Bi1-xBaxFeO3(named as BBFO-x,x=0,0.05,0.15)were prepared by the sol-gel method with rapid thermal process.In order to obtain pure bulk ceramics with enhancing magnetic properties,the effect of Ba-doping and process conditions on the structure and magnetic properties of the samples have been well investigated.Second,based on the above investigation,the microstructure and magnetoelectric coupling effect in such single phase multiferroics have been further studied.In detail,we carefully characterise the microstructure of the Bi0.95Ba0.05FeO3 ceramics by using SEM,XPS.Then,the electric field modulation of magnetism in Bi0.95Ba0.05FeO3 ceramics at room temperature is especially investigated.The last,considering the device miniaturization and optimization of material physical properties,we carry out the research about preparation and performance for Bi0.95Ba0.05FeO3 thin film.Namely,the pure phase of Bi0.95Ba0.0sFeO3 thin films are prepared by PLD with the quartz and ITO glass as substrate,respectively.The best process conditions to prepare the Bi0.95Ba0.05FeO3 thin films have been obtain.And the structure,magnetic and photovoltaic properties were studied.