Evidence of magnetism in RF magnetron sputtered deposited carbon films and investigation of its origin
| Autor: | G. Amarendra, Sujay Chakravarty, Reddy Ss, U.P. Deshpande, Balaram Thakur |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Analytical chemistry 02 engineering and technology General Chemistry Sputter deposition 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Magnetization symbols.namesake Carbon film Cavity magnetron symbols General Materials Science Crystallite Thin film 0210 nano-technology Raman spectroscopy Superparamagnetism |
| Zdroj: | Carbon. 154:485-496 |
| ISSN: | 0008-6223 |
| DOI: | 10.1016/j.carbon.2019.08.028 |
| Popis: | The origin of magnetism in RF magnetron sputtered deposited carbon thin films is reported. Three different carbon thin films were deposited using RF magnetron sputtering of carbon target by Ar ions at RF power of 50 W, 100 W and 150 W, respectively. Microstructural characterization of films using Raman spectroscopy confirms the presence of graphitic crystallites in all three films and the crystallite edges are terminated with the sp3 bonding. However, increasing RF power results in an increase in graphitic crystallite size as well as the sp2/sp3 hybridization ratio, while the average density of the films decreases. The observed magnetization (measured using SQUID-VSM) in all the three-carbon films has a contribution from both superparamagnetic (SPM) particles (due to the interaction between unpaired spins) and the paramagnetic term due to isolated unpaired spins distributed throughout the film. The origin of experimentally observed magnetization in the carbon thin films and their correlation with the change in density and sp2/sp3 hybridization ratio due to variation in RF power is discussed. |
| Databáze: | OpenAIRE |
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