An inductive measurement method was adopted to analyze the magnetic properties of magnetite nanopowders and the possibility to prepare samples having the same geometry is discussed from a macroscopic point of view. The influence of the chemical composition on magnetic and morphological characteristics of the samples was investigated by several measurement techniques with the aim to better investigate the observed magnetic effects. An innovative green Micro-Wave (MW)-assisted approach was used for the synthesis of magnetite (Fe3O4) nanopowder and of magnetic bimetallic systems M@Fe3O4 (M: Ru or Pd) and the effect of noble metals was observed. The structure and chemical identification of the synthesized materials were analyzed and correlated to the measured magnetic properties.