An investigation of the tape medium noise mechanism analyzed the magnetizat
ion fluctuation produced by an incremental de erase process in a variety of
modern metal-particle tape media. It examined the wavelength characteristi
cs of the noise and compared the integrated noise during the reverse de era
se process with in situ remanent hysteresis curves. The integrated noise po
wer followed the square of the first field derivative of the remanent hyste
resis 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 excl
uded spatial fluctuation of the medium coercivity as a possible noise sourc
e by comparing results from recording heads with two very different gap len
gths. A quantitative analysis of the medium noise spectra at different eras
e currents indicated that interfacial roughness at the magnetic coating bac
kside in some dual-layer media is a major source of medium noise. The concl
usion: The main mechanism of the medium noise in advanced tape media is the
head medium spacing fluctuation due to surface roughness.