A deep-rooted understanding of the mechanisms at atomistic level lends further support to the rapid development in ultrahigh density magnetic recording, in magnetic sensor technology or even in medical applications of magnetic nanoparticles. Short-range order (SRO) magnetic correlations seem to play an important role in the formation of local magnetic moments in paramagnetic Ni, while the ordering of different chemical elements at short-range can also remarkably influence the magnetic interactions in magnetic alloys. First principles based theoretical methods are highly useful to study such phenomena. In the proposed doctoral research work we intend to apply the Embedded Cluster Green's Function method within the Korringa-Kohn-Rostoker formalism to investigate the formation of local magnetic moments and the interactions between them in small ordered clusters embedded in magnetically and/or chemically disordered host systems. The latter ones are described in terms of the Coherent Potential Approximation (CPA) and the Relativistic Disordered Local Moment (RDLM) scheme, also available in the program package developed at our department. Our main objective is the study of the magnetism in Ni and in FeCo alloys, as well as in some disordered Heusler-compounds. Beyond the bulk state, we will extend our studies to surfaces, interfaces and to multilayer systems that might display an enhancement of SRO-induced correlations due to their reduced dimensionality.