The influence of Ni-doping concentration on multiferroic behaviors in Bi4NdTi3FeO15 ceramics

Ceramics of Ni-doped Bi4NdTi3Fe1−xNixO15 (x=0.1, 0.3, 0.5 and 0.7) (Nix) were synthesized by a multicalcination procedure. The substitution of Ni for Fe does not change the layered perovskite structure of Bi4NdTi3FeO15 (BNTF) except that a small amount of Ni2O3 appears in the Ni0.7 sample. Plate-like morphology of the grains which is characteristic for layer-structure Aurivillius compounds was clearly observed for all the Nix samples. The εr, 2Pr and 2Mr values are not proportional to the Ni doping concentration but increase firstly and then decrease. Taking into account ferroelectric and magnetic properties together the optimum room temperature (RT) multiferroic property was acquired in the Ni0.3 sample within the range of experiment, which is preliminarily discussed from the radius difference of magnetic ions, their ratio and the location of different magnetic ions. The present work is meaningful for compositional design of RT multiferroic materials based on four-layer structured Aurivillius compounds.