Initial magnetization curve of thin film media

The authors propose a novel approach for evaluating the signal-to-noise ratio (SNR) characteristics from the magnetic properties of thin film media such as CoCrTa, CoNi, and CoNi(Sm, Cr). The initial magnetization curve on the AC recorded state characterizes the domain wall motion. The maximum slope of (dM/dH)max correlated well with the SNR of the media. Among the tested samples, CoCrTa media showed the best SNR and the largest value of (dm/dH)max. Tantalum segregation observed in and around the CoCrTa grains seemed to enhance the uniform pinning effect and reduce the zig-zag domain formation. >