Volume 49 (2006)

MAGNETIC PROPERTIES OF SMALL AMOUNT OF Fe₂O₃ IN SILICAPOLYVINYL ALCOHOL MATRICES NANOCOMPOSITES
Pages 81-84
Claudia Ionescu, Cecilia Savii, Mark E. Smith, Corina Enache1, Ramona Radu1, Adriana Lancok, Daniel Niznansky, Karel Zaveta

Abstract
¹H and ²⁹Si MAS NMR, and Mössbauer spectroscopy of a prepared series of sol-gel Fe₂O₃-silica/PVA nanocomposites materials containing 0.1; 1; 2; 5; and 10% Fe₂O₃ are reported. The ²⁹Si NMR typically shows three Q-species (Q^2,3,4) in the initial gels, and as heat treatment temperature is increasing the average n of the Qⁿ-species increases as well. The observed behaviour can be attributed to the organic fragments and hydroxyl groups removal. The proton spectra reflect the proton-content decrease as the temperature of the heat treatment increases. For certain temperatures the grow and the stability of some phases are influenced by differential thermal treatment as the Mössbauer spectroscopy revealed.