Carmona Tejero, NoemíBouzas, V.Jiménez, F.Plaza, M.Pérez García, LucasGarcía, M. A.Villegas, M. A.LLopis, J.2023-06-202023-06-202010-03-040925-400510.1016/j.snb.2009.11.048https://hdl.handle.net/20.500.14352/42771©2009 Elsevier B.V. All rights reserved. Authors wish to thank XAFS Beamline BM25 (Spanish-SPLine CRG) at the European Synchrotron Radiation Facilities, ESRF (Grenoble, France). The funding of the EU project “BONSAI” LSHB-CT-2006-037639. NC acknowledges the financial support of the FSE-MEC, Ramón y Cajal program ref. RYC-2007-01715.Optical absorption and magnetic properties of silica sol-gel monoliths doped with cobalt starting from different precursors and water/1-propanol molar ratios are investigated. Structural characterization of the sol-gel by X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy corroborate, that oxidising state of cobalt is Co^(2+). Furthermore, the Co^(2+) first neighbors are O atoms displaying a temperature transition from octahedral to tetrahedral coordination. The doped monoliths show thermochromic sensor activity ranging from 10 to 50⁰ C, which is related to the environment of Co^(2+) ions. The magnetic susceptibility also varies with Co^(2+) ions environment due to changes in the orbital contribution to the magnetic moment. Thus, we achieve a better understanding about environment of the Co^(2+) ions in the gel matrix and explain their reversible temperature behaviour in spite of the rigid state of the host matrix.engjournal articlehttp://dx.doi.org/10.1016/j.snb.2009.11.048http://www.sciencedirect.comopen access538.9Magnetic-propertiesFilmsNanoparticlesTemperatureAbsorptionGlassesFísica de materialesFísica del estado sólido2211 Física del Estado Sólido