Room-temperature ferromagnetism in Fe-doped PbTiO3 nanocrystals.

Room-temperature ferromagnetism has been observed in Fe-doped PbTiO3 nanocrystals. The magnetism of the nanocrystals develops from diamagnetism to ferromagnetism and the paramagnetism on increasing nominal Fe doping concentration from 0 to 4 mol %. Transmission electron microscope (TEM) and high-resolution TEM data indicate that Fe-doped PbTiO3 nanocrystals with the size of ∼100 nm are organized to form a planarlike self-assembly via oriented aggregation. These assembled nanostructures effectively improve room-temperature ferromagnetism of the sample. The exchange interaction of ferric ions via an electron trapped in a bridging oxygen vacancy (F center) is employed to explain the ferromagnetism of Fe-doped PbTiO3 nanocrystals. [ABSTRACT FROM AUTHOR]