No abstract

The dependences of magnetic properties and effective damping parameter (αeff) on film-thickness (d) and growth temperature (Ts) for Fe69Co26Si5 alloy films are investigated. The saturation magnetization (Ms) are found to decrease from approximately 1,700 to 1,500 emu/cm3 with d for Ts = 230 °C. For 40 nm films, the magnetization remains constant over the entire range of Ts from 35 to 360 °C. The coercivity (Hc) values for Ts above 120 °C are approximately 20 Oe. Those films deposited at Ts =120 °C or higher are epitaxial with the relation of <100>FeCoSi//<110>MgO in the film plane. For the films deposited at Ts =230 °C, the αeff rapidly decreases, and then slightly increases with d. The minimum αeff value of 0.002 is obtained at Ts = 230 °C.

Fe 69 Co 26 Si 5 alloy thin films of various thicknesses were deposited on MgO(100) single crystal substrates by magnetron sputtering at 230 ℃ substrate temperature. The thickness dependence of the dynamic magnetic properties was investigated using broadband ferromagnetic resonance (FMR). The X-ray diffraction (XRD) results indicate that all films are of the bcc structure with an in-plane epitaxial alignment of [100] FeCoSi // [110] MgO. The exchange constant was determined from the field shift between the uniform precession FMR mode and the first order perpendicular standing spin wave (PSSW) resonance mode in the FMR spectra. The effective damping parameter decreases dramatically with increasing film thickness up to 16 nm due to the decrease of the spin pumping contribution and then remains relatively constant as the film thickness increases. In-plane angle dependent FMR measurements reveal that the in-plane anisotropy of these films are dominated by a four-fold magnetic anisotropy, which increases sharply with increasing film thickness up to 16 nm and then shows a slightly decreasing trend as the film thickness increases. In-plane angular dependence of the FMR linewidth shows a strong two-magnon scattering contribution.