The objective of this work is to understand how the deposition temperature and the nature of substrate can tune the structural and magnetic properties and the morphology of MxPt1-x (M=Co and Fe) nanostructured alloys. The metallic adatoms have been co-deposited by molecular beam epitaxy at different deposition temperature on low energy surfaces as WSe2(0001) and NaCl(001). The characterization has been performed by the using of several techniques. Reflection high energy electron diffraction (RHEED) has been use to follow the epitaxy growth during the deposition; the X-ray diffraction measurements (XRD) has been performed to characterize the structure and extrapolate the long range chemical order parameter; the X-ray absorption spectroscopy (XAS) has been use to probe the local structure; the magnetic anisotropy has been investigated by the superconducting quantum interference devices (SQUID); the morphology was studied by grazing incidence small angle x-ray scattering (GISAXS) measurements, coupled to other characterization techniques (TEM, STM and Field Emission-SEM). A first result is the structural anisotropy at short range observed in the CoPt3 grown at room temperature on WSe2(0001). It is characterized by preferential Co-Co correlations in the film plane extending up to third shell that suggests the formation of Co rich thin disks in the film plane. The cobalt segregation is accompanied with a lattice distortion, where the in-plane bonds are shorter than the out-of-plane bonds. These effects disappear for the samples prepared at higher deposition temperature, Td, in which partial L12 order and larger in-plane …