EFFECT OF THIN-FILM DISK TEXTURE ON MAGNETIC RECORDING SIGNALS

The effect of texturing on the readback signal of Co-alloy thin-film d isks is investigated. Instantaneous pulse area (PA) traces, representa tive of the magnetic signal strength, and instantaneous pulse width (P W50) traces, indicative of the transition resolution, are measured. Th e low-frequency, ''twice-around'' modulation is removed from these tra ces. The resulting PA fluctuations are small; the PW fluctuations are larger and closely correlated to the texture. Calibration of PW vs fly ing height allows comparison of the texture-induced head clearance mod ulation and the actual disk surface roughness. The texture causes sign al resolution (PW) noise which, for these head/disk combinations, is p redominantly due to the spacing loss variations during the readback pr ocess. The write process and any texture-related H(c) or M(r)t fluctua tions appear to contribute negligibly.