Enhanced multiferroic properties and tunable magnetic behavior in multiferroic BiFeO3-Bi0.5Na0.5TiO3 solid solutions

A series of multiferroic (1-x)BiFeO3-x(Bi0.5Na0.5)TiO3 (BF-BNT)(x= 0- 0.6) solid solution ceramics were prepared by a sol-gel method. The XRD results show that increasing BNT content induce a gradual phase transformation from rhombohedral to pseudocubic structure near x = 0.4. Compared with pure BiFeO3, superior multiferroic properties are obtained for x = 0.3 with remnant polarization P-r = 1.49 mu C/cm(2) and saturated magnetization M-s = 0.51 emu/g. Importantly, the paramagnetic (PM) to ferromagnetic (FM) transition is observed for the solutions, and the Curie temperature (T-c) can be tuned by varying the content of BNT. This observed FM ordering is discussed in terms of the possible existence of the long-range superexchange interaction of Fe3+-O-Ti-O-Fe3+ in the chemically ordered regions. (C) 2011 Elsevier B.V. All rights reserved.