Pure and Co-doped single-phase CeO2 crystals were synthesized by a solid-state

reaction method. Samples of different oxygen vacancy concentration were studied,

including (1) as-sintered crystals, (2) powders ground from the same crystal, and

(3) a cold-pressed pellet from the ground powder that was unannealed and annealed

at 800C. By analyzing the magnetic behaviors, surface/volume ratio and O vacancy

concentration, the effects of oxygen vacancies on the room-temperature

ferromagnetism (RT-FM) of Co-doped CeO2 were systematically investigated. The

results confirmed that the RT-FM observed in Co-doped CeO2 has a direct

relationship with the oxygen vacancy concentration, and support the oxygen

vacancy mediated FM mechanism.

Effects of Oxygen Vacancies on the Room-Temperature Ferromagnetism of Co-

Doped Polycrystalline CeO2. Q.Y.Wen, H.W.Zhang, Q.H.Yang, Y.Q.Song,

J.Q.Xiao: Journal of Magnetism and Magnetic Materials, 2009, 321[19], 3110-3