Ferromagnetism in sub-micron scale BiFeO3

Sub-micron scale BiFeO3 has been fabricated by annealing precursor powders prepared through microwave-assisted sol–gel self-combustion method. It is found that the content of glacial acetic acid is crucial to particle morphologies and magnetic properties. The average particle size for the final products increases from tens to hundreds of nanometers with increasing glacial acetic acid content. With the increase of particle size, room temperature ferromagnetic hysteresis loops along with remarkable improvement of saturation magnetizations have been observed in sub-micron (tens to hundreds of nanometers) BiFeO3, which in bulk form exhibits an antiferromagnetic order. These features may suggest that the magnetic properties of BiFeO3, at the sub-micron level, increase with increasing particle size.

► Sub-micron scale BiFeO3 has been fabricated. ► Particle size of final products is in the range of tens to hundreds of nanometers. ► The magnetization of BiFeO3 is greatly improved with the increase of particle size.