Measurement and control of high-energy Ar species in the magnetron plasma source is discussed. From energy distribution measurement of Ar+ in the plasma, existence of high-energy Ar atoms in the magnetron plasma source is confirmed. It is concluded that collision of high-energy Ar atom with background thermal Ar atom is the dominant ionization mechanism for the production of high-energy Ar+. Based on this ionization mechanism, a Monte Carlo code is developed to simulate the Ar+ energy distribution and the results are in good agreement with the experimental ones. A new technique to suppress high-energy Ar species i.e., VHF-DC superimposed magnetron sputter source, is proposed. Compared with conventional magnetron sputter sources, this new sputter source shows lower Ar energy, which is consistent with the simulation result. The VHF-DC superimposed magnetron plasma is successfully applied to the deposition of magnetic multilayer films with very thin (<1 nm) layer thickness and good magnetic anisotropy.