Enhancement of ferromagnetic properties in BiFeO3 polycrystalline ceramic by La doping

The authors present the structure transformation and magnetic properties of Bi1-xLaxFeO3 (x=0.0-0.15) ceramics prepared by a conventional solid-state reaction processing. Magnetic measurements reveal that remnant magnetization of 15% La-doped BiFeO3 has enhanced about 20 times as compared to pure BiFeO3. It is the structural phase transition (R3c-C222) near x=0.15 that destructs the spin cycloid, and thus enhances the ferromagnetic properties significantly. In these Bi1-xLaxFeO3 ceramic samples, besides the known antiferromagnetic Neel temperature T-N1 similar to 615 K, another Neel temperature T-N2 similar to 260 K can be observed due to the trace impurity phase of Bi2Fe4O9 in these ceramic samples. (c) 2007 American Institute of Physics.