Attention is given to problems of the interaction of surfactant (SFT) molecules and ferromagnetic metal particles via polar/apolar contacts. In particular, the influence of anionic and cationic SFT in water-based systems on the changes of magnetic characteristics and particle shape is studied. For the experiments the Co/sub 70.4/Fe/sub 4.6/Si/sub 15/B/sub 10/ composition was selected because of its soft magnetic properties and low value of the magnetostriction coefficient. Ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) were used to analyze the details of the grinding process as well as the influence of the surfactants on the structure, morphology, and magnetic properties. The magnetic data are compared with microstructure and macrostructure, determined from transmission electron micrographs and selected-area electron diffraction patterns. A strong influence of different surfactants and milling times on the particle shape, magnetic saturation, and anisotropy was observed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>