Magnetic Cluster Size Distribution and Its Relation to Read/Write Performance From Spinstand Testing

We have developed an analysis method that uses spinstand tester to estimate magnetic cluster size distributions, including average size and size deviations. To statistically analyze the alternating current (ac)-erased magnetization distribution, the autocorrelation functions of the magnetization distributions were derived from readback media noise spectra. The cluster size distributions were quantified from the autocorrelation function by utilizing the undershoot value as well as the zero-crossing shift length. Good agreement with minor-loop analysis supported the validity of this method. This method will be useful for developing media because measuring is easy, fast, and can be used for various kinds of recording media under a variety of conditions. The relationship between the transition jitter and the magnetic cluster size distributions were clarified by regression analysis. The results showed reducing the average cluster size should be the first priority, and lowering size deviation should be the second.