Magnetic and electric properties of Co-doped Bi5 Ti3 FeO15 multiferroic ceramics

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 four-layer 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 (2M(r)) 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 (2P(r)) reaches a value of 11 mu C/cm(2) 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.