Magnetic probing of tunable Eu/sup 3+/ local site in organic-inorganic nanohybrids

The magnetic properties of sol-gel derived Eu/sup 3+/-doped organic/inorganic hybrid nanocomposites were studied. These hybrids consist of poly(oxyethylene)-based chains of variable length grafted onto siloxane nanodomains by urea cross-linkages. Results are presented for two chain length series, for which the local environment of Eu/sup 3+/ ions and the urea-urea interactions induce distinct magnetic behaviors. For high Eu/sup 3+/ content strong thermal irreversibility effects are found, due to the presence of Eu/sup 3+/ magnetic interactions in the nanodomains.