Room-Temperature Ferromagnetism in Co-Doped In 2 O 3 Nanocrystals

Co-doped In 2 O 3 nanocrystals showing room-temperature ferromagnetism have been successfully prepared by a simple sol−gel synthesis route. The sample displays a clear ferromagnetism behavior above 300 K. Phase and structure analyses reveal that the nanocrystals are crystallized with Co ions substituted for In ions in the In 2 O 3 matrix, and no trace of secondary phases or clusters is detected. The experimental results are explained theoretically by first-principles calculations based on density functional theory, which indicate that the native ferromagnetic behavior of Co-doped In 2 O 3 could be mainly ascribed to the strong d−d coupling of the magnetic ions.