Paramagnetic behavior of Co doped TiO2 nanocrystals controlled by self-purification mechanism
| Autor: | M. Abdul Khadar, B. Anitha, Alok Banerjee |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Anatase
Analytical chemistry chemistry.chemical_element 02 engineering and technology 01 natural sciences law.invention Inorganic Chemistry Tetragonal crystal system symbols.namesake law 0103 physical sciences Materials Chemistry Organic chemistry Physical and Theoretical Chemistry 010306 general physics High-resolution transmission electron microscopy Electron paramagnetic resonance Dopant Doping 021001 nanoscience & nanotechnology Condensed Matter Physics Electronic Optical and Magnetic Materials chemistry Ceramics and Composites symbols 0210 nano-technology Raman spectroscopy Cobalt |
| Zdroj: | Journal of Solid State Chemistry. 239:237-245 |
| ISSN: | 0022-4596 |
| Popis: | Doping in nanocrystals is a challenging process because of the self- purification mechanism which tends to segregate out the dopants resulting in a greater dopant concentration near the surface than at the interior of nanocrystals. In the present work nanocrystals of TiO 2 doped with different atom % of Co were synthesized by peroxide gel method. XRD analysis confirmed the tetragonal anatase structure and HRTEM images showed the rod-like morphology of the samples. Raman modes of anatase phase of TiO 2 along with weak intensity peaks of Co 3 O 4 for higher Co dopant concentrations were observed for the samples. EPR measurements revealed the presence of cobalt in +2 oxidation state in the TiO 2 matrix. SQUID measurements indicated paramagnetic behavior of the Co doped TiO 2 nanocrystals. The paramagnetic behavior is attributed to an increased concentration of Co 2+ ions and an increased presence of Co 3 O 4 phase near the surface of the TiO 2 nanocrystals due to self-purification mechanism. |
| Databáze: | OpenAIRE |
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