Magnetic performance and corrosion resistance of cobalt based magnetic films

Abstract

To optimise the composition of magnetic materials applied in the fabrication of ultralarge scale integration (ULSI) devices and microelectromechanical systems (MEMS), the magnetic performance and anticorrosion property of cobalt based magnetic films (CoWP, CoPtP and CoMoP) were investigated using vibration sample magnetometer (VSM) and electrochemical technologies (potentiodynamic polarisation curve and electrochemical impedance spectroscopy). Results indicate that CoWP has a small coercivity (592·73 Oe) and large saturation magnetisation value (144·20 emu.g⁻¹); while CoPtP and CoMoP films are hard magnetic materials with coercivity of 1786·57 and 2745·20 Oe, saturation magnetisation value of 91·72 and 120·74 emu.g⁻¹ respectively. Electrochemical measurements reveal the order of corrosion resistance in 3·5%NaCl solution was CoPtP film>CoWP film>CoMoP film. In the fabrication of ULSI devices and MEMS, CoPtP film was recommend to be one of the most suitable magnetic materials. CoPtP film was thick with finer grains (52–78 nm) and lower roughness (18·212 nm).