Morphology-Controlled Synthesis of CeO2 Microstructures and Their Room Temperature Ferromagnetism

Gear-shape CeO 2 microstructures have been synthesized via a facile hydrothermal method with Ce(NO 3 ) 3 ⋅6H 2 O as the cerium source, NH 4 HCO 3 as both the precipitator and the carbon source, and cetyltrimethyl ammonium bromide (CTAB) as the surfactant. X-ray diffraction (XRD) inferred that the synthesized CeO 2 microstructures exhibited a fluorite structure. The band gap ( E g ) of CeO 2 samples is larger than that of bulk. X-ray photoelectron spectroscopy (XPS) showed that there are plenty of Ce 3+ ions and oxygen vacancies at the surface of CeO 2 samples. All the synthesized CeO 2 samples exhibited the room temperature ferromagnetism, and the saturation magnetization increases with the increases of lattice parameter and E g . The room temperature ferromagnetism mechanism of gear-shape CeO 2 is mainly attributed to the influence Ce 3+ ions.