Magnetic Properties and High Frequency Application of the Multi-component Soft Magnetic Thin Film Fabricated by RF Magnetron Sputtering

• Main Authors: Hung-Kai Chen, 陳弘凱
• Other Authors: Shih-Hai Li
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/78957385318570506584

碩士 === 國立清華大學 === 工程與系統科學系 === 93 === Soft magnetic properties with suitable uniaxial anisotropy and high saturation magnetization are required for the high frequency application. In this study, multicomponent Fe-Co-Ni-based soft magnetic thin films were deposited on the Si substrate by RF magnetron sputtering at room temperature. Various nitrogen contents were added during sputtering by adjusting the N2 gas flow. The composition, crystal structure and magnetic domain were analyzed by using electron probe microanalyzer (EPMA), X-ray diffraction (XRD) and magnetic force microscope (MFM), respectively. Without nitrogen doping, the domain of the magnetic thin film was arranged randomly with the thickness around 1μm. The effect of N2 content in the thin film on the magnetic properties was evaluated and further discussed. Magnetic properties, including saturation magnetization (Ms), coercivity (Hc) and anisotropy field (Hk), were evaluated with a vibrating sample magnetometer (VSM) and Magneto-Optics Kerr Effect (MOKE). For the as-deposited magnetic thin films, no anisotropy magnetization was observed. However, a distinct uniaxial anisotropy occurred after annealed at 300 °C for 1 hr under 1200 Oe external in-plane magnetic field when the nitrogen was added. The saturation magnetization (Ms) of the as-deposited magnetic thin films without nitrogen doping was about 17 kG, and no anisotropy was revealed after field annealing. In contrast, when the nitrogen was added, the anisotropy field (Hk) increased to 30 Oe, while Ms slightly decreased to 13 kG. The high frequency behavior of Fe-Co-Ni-based magnetic thin films was also evaluated. For the ferro-magnetic resonance frequency (fFMR) correlated to the product of Ms and Hk, a value as high as 2.5 GHz was derived for the annealed N2-doped magnetic thin film.