Production and studies of properties of nanopowders on the basis of CeO2
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Nanopowders (NPds) of pure CeO2 of a specific surface area up to 210 m2/g and those doped with copper, carbon, and iron (≤1 wt % of dopant) of a specific surface area in the range 130–160 m2/g have been produced by evaporation with a pulsed electron beam. According to the X-ray phase analysis data, no secondary phases (aside from the cubic CeO2 phase) were found in the produced NPds. All the powders contained fine- and coarse-crystalline fractions differing in the size of their coherent scattering region (CSR) and in their amorphous component. The degree of crystallinity of the powders was not above 22%. The powders have a fractal structure and consist of agglomerates of sizes from dozens to hundreds of nanometers formed by crystalline nanoparticles (NPts) 3–5 nm in size with a very narrow particle size distribution. NPds have a high structural defectiveness degree, which was reflected in their magnetic properties. The room ferromagnetism was established in NPds of pure CeO2 − x and those doped with nonmagnetic elements (carbon and copper): here the ferromagnetic state in the CeO2-C system was established for the first time, whereas the magnetic moment on the carbon atom was 35-fold lower than the theoretical estimation. The ferromagnetic contribution to CeO2 NPd increases with a decrease in the NPt size and reaches 0.1 emu/g in CeO2-Fe NPd (x Fe = 0.54 wt %). It has been established that there is no direct dependence between magnetization and the content of iron ions in the CeO2-Fe-based NPds.
KeywordsCoherent Scattering Region Room Temperature Ferromagnetism Pulse Electron Beam Cerium Dioxide Micron Powder
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- 8.Ya. A. Kotov, S. Ya. Sokovnin, and C. K. Rhee, “Modernization of the Installation for Production of Nanopowders of Metal Oxides Using Pulsed Electron Beam,” in Proceedings of the 9th International Conference on Modification of Materials with Particle Beams and Plasma Flows (IAO SB RAS, Tomsk, 2008), p. 734.Google Scholar
- 12.S. A. Suevalov, XRLEdit — Editor of Primary Processing of Diffractometric Data, V. 2.98.2005. http://xray.physics.usu.ru
- 13.A. K. Shtol’ts, A. I. Medvedev, and L. V. Kurbatov, in X-Ray Analysis of Microtensions and the Size of Coherent Scattering in Polycrystalline Materials, the Electron School-Book, Ed. by L. V. Kurbatov (GOU VPO UGTU-UPI, Ekaterinburg, 2005), p. 23 [in Russian].Google Scholar
- 14.A. E. Baranchikov, O. S. Polezhaeva, V. K. Ivanov, and Y. D. Tretyakov, “Lattice Expansion and Oxygen Non-Stoichiometry of Nanocrystalline Ceria,” R. Soc. Chem., Cryst. Eng. Commun. 12, 3531–3533 (2010).Google Scholar
- 23.P. K. Slusser, “Transition Metal Doped Oxide for Spintronics Applications,” Master of Science Thesis (Department of Materials Science and Engineering, Univ. of Utah, 2009), p. 95.Google Scholar
- 35.S. Yu. Sokovnin, V. G. Il’ves, A. I. Medvedev, A. M. Murzakaev, A. V. Spirina, and M. A. Uimin, “Production of Al2O3-Al(Cu) Nanopowders by Pulsed Electron Beam Evaporation and Their Basic Characteristics,” in Proceedings of the 10th International Conference on Modification of Materials with Particle Beams and Plasma Flows (IAO SB RAS, Tomsk, 2010), p. 783.Google Scholar
- 37.S. Yu. Sokovnin, V. G. Il’ves, A. I. Medvedev, A. M. Murzakaev, and M. A. Uimin, “Pulse Electron Evaporation of ZnO-Zn Nanopowders Doped by Copper,” in Proceedings of the 4th All-Russia Conference on Nanomaterials, Moscow, 1–4 March 2011 (IMET RAN, Moscow, 2011), p. 574.Google Scholar