Influence of film thickness on the soft magnetic properties of sputtered Co‐Fe‐Hf‐O films

Influence of film thickness on the soft magnetic properties of Co19.35Fe53.28Hf7.92O19.35 films, which were deposited on Si(100) substrates using the oxygen reactive RF-sputtering method, has been thoroughly investigated. It is found that as the film thickness (t) increases from 50 to 430 nm, the easy-axis coercivity (HCE) strongly decreases from 26.2 to 1.5 Oe, while the hard-axis anisotropy field (HKH) significantly increases from 68.7 to 84.8 Oe and the saturation magnetization (4πMs) tends to increase from 16.8 to 19.7 kG. As t exceeds 430 nm, HKH gradually decreases, while both HCE and 4πMs remain almost unchanged. It reveals that a strong phase separation appears to occur in films with t > 430 nm, resulting in the decrease of HKH. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)