Co掺杂Bi_5Ti_3FeO_(15)多铁陶瓷的磁电性能

Magnetic and electric properties of Co-doped Bi_5 Ti_3 FeO_(15) multiferroic ceramics

采用了传统的固相烧结工艺制备出Bi5Fe1-xCoxTi3O15(BFCT-x,x=0.0—0.6)多铁陶瓷样品,研究了Co掺杂对Bi5FeTi3O15(BFTO)微观结构、铁电和磁性能的影响.X射线衍射谱显示样品均已形成四层铋系层状钙钛矿相,且随着掺杂量的增加发生了结构变化.拉曼光谱进一步证实掺入的Co占据了B位,并且Co的掺杂对B位离子的有序排列产生了影响.掺杂后样品在室温下显示为铁磁性,磁性能得到了显著的改善,剩余磁化强度(2Mr)在掺杂量x=0.5时达到最大值,为2.3memu/g,是未掺杂时的1000倍.在不同Co含量下,BFCT-x样品都具有铁电性,但随掺杂量x的增加,剩余极化强度(2Pr)呈现先增加,减小后又增加的趋势.当掺杂量x=0.1时,样品的铁电性能最好,2Pr=11μC/cm2,比未掺杂时提高了38.2%.实验得到综合性能最佳的Co掺杂样品为BFCT-0.5,在室温下能同时具备良好的铁电和铁磁性能.

Multiferroic ceramics of Bi5Fe1-xCoxTi3O15（x = 0.0—0.6） are synthesized by the conventional solid state reaction,and their microstructure,magnetic and ferroelectric properties are investigated.X-ray diffraction patterns show that a fourlayer Aurivillius phase is formed in each sample with a suggested structural transformation at heavy doping of Co ions.The Raman results demonstrate that Co ions enter into the lattice,occupy the B-sites in the BFCT-x and have an effect on the order occupancy of cations at B sites.It is found that the Co ion modification induces remarkable ferromagnetism （FM） at room temperature with a greatest remanent magnetization （2Mr ） of 2.3 memu/g at x = 0.5,which is three orders of magnitude larger than that of Bi5Ti3FeO15（BFTO）.All samples with Co doping have ferroelectricity （EM）.The remanent polarization （2Pr） reaches a value of 11 μC/cm2 at x = 0.1,which is about 38.2% higher than that of BFTO,and then decreases when 0.2≤x≤0.4 and increases again at x = 0.5 and 0.6.Of all materials,the sample of x = 0.5 is best in both good FE and FM.