Planar assembly of monodisperse metallic cobalt nanoparticles embedded in TiO2-delta matrix

B. Vodungbo (1) , Y. Zheng (1) , M. Marangolo (1) , D. Demaille (1) , J. Varalda (2)

1 INSP - Institut des Nanosciences de Paris
2 IMPMC - Institut de minéralogie et de physique des milieux condensés

We report the growth of a single layer of metallic cobalt nanoparticles in a TiO2-delta matrix. The films are grown by pulsed laser deposition ( PLD). Transmission electron microscopy ( TEM) is used to determine the morphology of the system and the crystalline structure ( HCP and/ or FCC) of the cobalt nanoparticles. A sharp interface between the nanoparticles and the matrix is observed. Electron energy loss spectroscopy ( EELS) is used to investigate the metallic character of the cobalt. Oxidation of cobalt at the interface with the matrix is not observed. With regards to the importance of the matrix for transport properties and because of the great variability of the oxygen content of TiO2-delta, efforts were also made on the analysis of TiO2-delta matrix. EELS measurements indicate an oxygen deficiency with respect to the nominal TiO2 composition which increases with growth temperature. This leads to a rather low resistivity of the matrix which also decreases with increasing growth temperature.

Domaines: Matière Condensée [cond-mat]

B. Vodungbo, Y. Zheng, M. Marangolo, D. Demaille, J. Varalda. Planar assembly of monodisperse metallic cobalt nanoparticles embedded in TiO2-delta matrix. Journal of Physics: Condensed Matter, 2007, 19 (11), pp.116205. ⟨10.1088/0953-8984/19/11/116205⟩. ⟨hal-01293149⟩