Structure and Magnetic Properties of Co₄₀Fe₄₀V₂₀ Thin Films

This study investigated the structure and magnetic properties of Co₄₀Fe₄₀V₂₀ thin films with a thicknesses (t) of 10 nm to 100 nm on a glass substrate. The X-ray diffraction (XRD) patterns of the CoFeV films demonstrated a significant crystalline body-centered cubic (BCC) CoFe (110) structure when the thickness was between 60 and 100 nm, and an amorphous status were shown when the thickness was from 10 to 50 nm. The strongest crystalline XRD peak was at 60 nm because it had a continuous mode of film growth and induced a large grain distribution. The low-frequency alternating current magnetic susceptibility (ϰac) property decreased when the frequency increased. The lowest ϰac value was detected at 60 nm owing to the large grain distribution inducing high coercivity (H) and then enhancing the spin coupling strength. The external field (H) was difficult to rotate spin state, then deduces the spin sensitivity and ϰ_ac value is decreased. The highest ϰ_ac meant the spin sensitivity was maximized at the optimal resonance frequency. The 50-mm thickness had the highest ϰ_ac 0.045 value at an f_res of 100 Hz. The f_res value was less than 1000 Hz at all CoFeV thicknesses, suggesting that CoFeV films would be suitable for low-frequency magnetic component applications. Moreover, the saturation magnetization (M) revealed a thickness effect when the thicknesses had a larger M. The H values were between 3 Oe and 10 Oe at all CoFeV films, except for 60 nm. The H of the 60 nm film was about 80 Oe due to the larger grain distribution, and it induced strong remanent magnetization (M) and a larger squareness ratio (M) of 92%. The results of the magnetic measurement showed that the 60 nm Co₄₀Fe₄₀V₂₀ film had greater H and a good squareness ratio.