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

A series of multiferroic (1− x )BiFeO 3 − x (Bi 0.5 Na 0.5 )TiO 3 (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 BiFeO 3 , superior multiferroic properties are obtained for x = 0.3 with remnant polarization P r = 1.49 μC/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 Fe 3+ –O–Ti–O–Fe 3+ in the chemically ordered regions.