Room-temperature ferromagnetism in Bi–Bi₂O₃ nanocomposite particles

Bi–Bi₂O₃ nanocomposite particles, with average particle size between 22 and 1300 nm, were prepared in a levitation–jet aerosol generator during a condensation of the bismuth vapor in mixed flows of inert gases with air. X–ray diffraction established in the particles the both phases of Bi and Bi₂O₃. It was discovered that the nanoparticles exhibit of a ferromagnetic behavior at room temperature. After a long duration of room-temperature aging, an enhancement in the magnetization was established. The maximum value of saturation magnetization observed in the studied nanocomposite particles was about 0.2 emu/g. It is proposed that an existence and interaction of intrinsic defects produced local paramagnetic states on the surface of nanoparticles and in interfacial areas is an origin of such magnetic phenomenon.