Dynamic magnetic properties of diluted systems of 4.7% and 9.8% volume fraction Co nanoparticles embedded in a Mn matrix are reported. The Co nanoparticles with an average size of 1.8 nm were prepared using a gas aggregation cluster source and a molecular beam epitaxy (MBE) source. The system displays irreversibility and signs of nonequilibrium dynamics at low temperatures which were studied in comparison to two model spin glass (SG) systems. The dynamic magnetic properties are investigated by means of zero-field-cooled (ZFC) magnetic memory effect measurements. \ua9 2010 IOP Publishing Ltd
