Serrano, A., A.Plaza, M.Pérez García, LucasVenta, J. de laLLopis, J.García, M. A.2023-06-202023-06-202009-041098-012110.1103/PhysRevB.79.144405https://hdl.handle.net/20.500.14352/42777©2009 The American Physical Society. Artículo firmado por más de diez autores. This work was supported by the Spanish Council for Scientific Research through the CSIC Projects No. 2006- 50F0122 and No. 2007-50I015 and Spanish Ministry of Science and Education through the Projects No. MAT2007- 66845-C02-01 and No. FIS-2008-06249. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities, and we would like to thank the SpLine CRG Beamline staff for assistance during x-ray absorption experiments.We report here the observation of ferromagnetism (FM) at 300 K in mixtures of TiO₂ and Co₃O₄ powders despite the antiferromagnetic and diamagnetic characters of both oxides, respectively. The ferromagnetic behavior is found in the early stages of reaction and only for TiO₂ in anatase structure; no FM is found for identical samples prepared with rutile-TiO². Optical spectroscopy and x-ray absorption spectra confirm a surface reduction of octahedral Co^(+3) -> Co^(+2) in the mixtures which is in the origin of the observed magnetism.engjournal articlehttp://dx.doi.org/10.1103/PhysRevB.79.144405https://journals.aps.orgopen access538.9Magnetic semiconductorsOxidesZnOFísica de materialesFísica del estado sólido2211 Física del Estado Sólido