The doping effects of BiFe1-xCoxO3 （x=0.0-0.8） in layered perovskite BiaTi3O12 ceramics

BisFe1-xCoxTi3O15 （x=0.0, 0.2, 0.4, 0.5, 0.6, and 0.8） multiferroic ceramics are synthesized in two steps using the solid state reaction technique. X-ray diffraction patterns show that the samples have four-layer Aurivillius phases. At room temperature （RT）, the samples each present a remarkable coexistence of ferromagnetism （FM） and ferroelectricity （FE）. The remnant polarization （2Pr） reaches its greatest value of 14 gC/cm2 at x = 0.6. Remnant magnetization （2Mr） first increases and then decreases, and the greatest 2Mr is 7.8 menu/g when x = 0.5. The magnetic properties for x = 0.4 are similar to those for x = 0.6, indicating that the magnetic properties originate mainly from the coupling between Fe3＋ and Co3＋ ions, rather than from their own magnetic moments.