@article{Savchenko2021spqeo24n2p124,
  title = {EPR study of paramagnetic centers in SiO2:C:Zn nanocomposites obtained by infiltration of fumed silica with luminescent Zn(acac)2 solution},
  author = {Savchenko, D.V. and Memon, V.S. and Vasin, A.V. and Kysil, D.V. and Rusavsky, A.V. and Kuz, O.P. and Gareeva, F.M. and Kalabukhova, E.N.},
  journal = {Semiconductor Physics, Quantum Electronics \& Optoelectronics},
  volume = {24},
  number = {2},
  pages = {124--130},
  year = {2021},
  doi = {10.15407/spqeo24.02.124},
  url = {https://doi.org/10.15407/spqeo24.02.124},
  abstract = {Silica-carbon with zinc (SiO2:C:Zn) nanocomposites obtained via infiltration with aged luminescent zinc acetylacetonate (Zn(acac)2) ethanol solution of two concentrations (1 or 4\%) into the fumed silica (SiO2) matrix have been studied using EPR within the temperature range 6…296 K before and after thermal annealing. The EPR spectrum of SiO2:C:Zn nanocomposites consists of three signals with the Lorentzian lineshape corresponding to paramagnetic centers with S = 1/2, which are related to carbon dangling bonds (CDB) (g = 2.0029(3)), silicon dangling bonds (g = 2.0062(3)) and oxygen-centered carbon-related radicals (CRR) (g = 2.0042(3)). A small EPR linewidth (<1 mT) observed for CDB and oxygen-centered CRR allows us to conclude that they are in the sp3-hybridized state. It was found that the temperature dependence of the EPR signal integrated intensity of the CDB and oxygen-centered CRR follows the Curie–Weiss law with a small positive value of the Curie–Weiss constant, which indicates that the weak ferromagnetic exchange interaction takes place in the spin system of CDB and oxygen-centered CRR. It was supposed that the carbon-related centers are clustered in SiO2:C:Zn nanocomposites. We assume that the oxygen-centered CRR in the sp3-hybridized state are associated with luminescent centers in previously reported aged Zn(acac)2/C2H5OH solution.},
  keywords = {silica-carbon nanocomposites, carbon-related centers, dangling bonds, exchange interaction, electron paramagnetic resonance}
}