FONSECA, F.C.GOYA, G.F.JARDIM, R.F.CARRENO, N.L.V.LONGO, E.LEITE, E.R.MUCCILLO, R.2014-07-312014-07-312014-07-312014-07-312003FONSECA, F.C.; GOYA, G.F.; JARDIM, R.F.; CARRENO, N.L.V.; LONGO, E.; LEITE, E.R.; MUCCILLO, R. Magnetic properties of Ni:SiO2 nanocomposites synthesized by a modified sol-gel method. <b>Applied Physics A</b>, v. 76, n. 4, p. 621-623, 2003. DOI: <a href="https://dx.doi.org/10.1007/s00339-002-2029-9">10.1007/s00339-002-2029-9</a>. Disponível em: http://repositorio.ipen.br/handle/123456789/7485.0947-8396http://repositorio.ipen.br/handle/123456789/7485Ni nanoparticles embedded in an amorphous SiO2 matrix were produced by a modified sol-gel method. This method resulted in nanocomposites with a controlled size distribution and good dispersion of the metallic particles. The particle-size distributions were found to have an average radius of ∼3 nm, as inferred from transmission electron microscopy, X-ray-diffraction analysis, and magnetic measurements. Magnetic characterizations revealed that samples exhibit superparamagnetic behavior above the blocking temperature TB, 20 K ≤ TB ≤ 40 K, and absence of a shift along the field axis on hysteresis loops measured at T ≤ TB, indicating that the metallic nanoparticles are also free from an oxide layer.621-623openAccesscomposite materialsnickelsilicon oxideschemical preparationcitric acidsilicatesparticle sizemagnetic propertiestemperature range 0013-0065 ksuperparamagnetismtransmission electron microscopyx-ray diffractionArtigo de periódico47610.1007/s00339-002-2029-9https://orcid.org/0000-0002-8598-279X