Hydrothermal synthesis, structural analysis and room-temperature ferromagnetism of Y2O3:Co2+ nanorods

• Hydrothermal synthesis of pure and Co-doped Y2O3 nanorods.
• Formation of nanorods without any template.
• Pure Y2O3 nanorods exhibited diamagnetism.

Co2+-doped Y2O3 nanorods of 70–100 nm diameters and 0.3–2 µm lengths with different compositions (x=0.00, 0.04, 0.08) in Y2−xCoxO3 were synthesized by an easy hydrothermal method. The X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy and transmission electron microscopy (TEM) results indicated the formation of a pure cubic phase structure of Y2O3 doped with Co2+ ions without any secondary phase formation. The TEM analysis indicated that the nanorods were grown along the [100] axis. The pure Y2O3 nanorods showed diamagnetism whereas the Co2+-doped ones exhibited room-temperature ferromagnetism. The existence of such room-temperature ferromagnetic behavior in Co2+-doped Y2O3 nanorods is due mainly to the existence of oxygen vacancies originating after the doping of transition metal ions in the Y2O3 host lattice. Oxygen vacancies act as defect centers in the bound magnetic polaron model to account for this dilute magnetic oxide of medium band gap with low transition-metal-ion concentration. The presence of defect-related oxygen vacancies was further confirmed by photoluminescence spectra analysis of our studied materials.