Transition and dc noise characteristics of longitudinal recording media were studied as a function of orientation ratio (OR). With increasing OR, a substantial decrease of dc noise is observed against the gradually increasing transition noise, resulting in the reduced media total noise. The increase in the media transition noise with OR is attributed to the increase in the cross-track correlation length s. The experimentally estimated s for the media with OR = 1.8 is significantly larger than that of the media with OR = 1.25, possibly resulting from the difference in magnetostatically coupled Co grains aligned to the track direction. For high-density low M{sub}rt designs, reducing dc noise by increasing OR, in spite of an increase in transition noise, becomes an effective means to increasing areal density.
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