High Frequency Characteristics of Fe₆₅Co₃₅ Alloy Cluster-Assembled Films Prepared by Energetic Cluster Deposition

Size-monodispersed Fe₆₅ Co₃₅ alloy clusters whose average sizes ranged from 7 to 12 nm were produced by a plasma-gas-condensation (PGC)-type cluster deposition apparatus. Fe₆₅Co₃₅ alloy cluster-assembled films were further prepared at room temperature by energetic cluster deposition method. Positively charged clusters in a cluster beam were accelerated electrically and deposited onto a negatively biased substrate together with neutral clusters from the same cluster source, leading to the formation of a high-density Fe₆₅Co₃₅ alloy cluster-assembled films with good soft magnetic properties. High frequency magnetic characteristics of these films were studied at room temperature using a high-frequency permeameter (RMF-3000, Ryowa). The real part (μ′) of permeability for the Fe₆₅Co₃₅ alloy cluster-assembled films prepared at bias voltage V _a = −20 kV has a large value of μ′ = 135 at f = 1.5 GHz, and imaginary part (μ″) of permeability has a maximum (μ″ ≈ 190) at about 2.5 GHz.