Comparison between different methods of determining anisotropy constants of thin film media

The magnetic anisotropy K-u value of Co81Cr15Ta4 polycrystalline thin film medium was determined by using the 45 degree magneto-torque and the rotatio nal hysteresis methods and compared with those of Co-Cr-Ta single crystal f ilms with different Cr contents. The anisotropy field H-k of polycrystallin e specimen determined by the rotational hysteresis method is confirmed to h e underestimated. The K-u of the Co-Cr-Ta polycrystalline film determined b y using the 45 degree magneto-torque method showed a reasonable agreement w ith that estimated from the single crystal specimen by taking into account of the Cr segregation in the polycrystalline grains.