Quantifying advanced tape medium noise

An investigation of the tape medium noise mechanism analyzed the magnetization fluctuation produced by an incremental dc erase process in a variety of modern metal-particle tape media. It examined the wavelength characteristics of the noise and compared the integrated noise during the reverse dc erase process with in situ remanent hysteresis curves. The integrated noise power followed the square of the first field derivative of the remanent hysteresis curve, (dM/dH)² , showing that spatial fluctuation of the recording field inside the medium is a major source of the tape medium noise. It excluded spatial fluctuation of the medium coercivity as a possible noise source by comparing results from recording heads with two very different gap lengths. A quantitative analysis of the medium noise spectra at different erase currents indicated that interfacial roughness at the magnetic coating backside in some dual-layer media is a major source of medium noise. The conclusion: The main mechanism of the medium noise in advanced tape media is the head medium spacing fluctuation due to surface roughness