Particle distributions and noise in metal particle tapes

The magnetization spectrum from an erased (ac demagnetized or dc saturated) particulate medium was derived analytically using the autocorrelation function of a long line of separate and contiguous particles. The derived expressions indicated a strong dependence on the percentage of chains and their length inside the magnetic medium. Using the values of these quantities as fitting parameters, good agreement to measured noise spectra from a digital tape system was obtained.