The low energy cluster beam deposition technique (LECBD) is used to prepare nanostructured thin films from clusters (Co, Ag, and mixed Co-Ag) preformed in the gas phase. Two dimensional (2D)-films of isolated supported clusters randomly distributed on the substrate, as well as isolated clusters embedded in various matrices by a co-deposition technique are prepared. Magnetic properties of Co-clusters films with equivalent Co-thickness as low as 0.01 nm are investigated using the extraordinary hall effect (EHE) measurements. The results emphasize the very high sensitivity of the EHE-technique to study the magnetic behaviour of very thin cluster films. Complementary transmission electron microscopy observations and X-ray photoemission spectroscopy measurements (XPS) on mixed Co-Ag clusters are also performed to investigate on the cluster morphology (homogeneous CoAg-alloy or core-shell structure due to the surface segregation of Ag-atoms) which could influence the corresponding magnetic properties. (C) 2003 Elsevier B.V All rights reserved.