An Experimental Study of Effects of Interlayer Thickness on Recording Performance Under Various Writing and Reading Clearances

We have experimentally investigated the effects of the interlayer thickness on recording performance, which was measured under various head clearances during writing and reading. In all cases, overwrite and write width always increase as the interlayer thickness is reduced. The signal-to-noise ratio, however, has a more complex dependence on the interlayer thickness: when the interlayer thickness is reduced, SNR is improved if head clearance during writing is large but is degraded if the head clearance during writing is small; SNR's dependence on the interlayer thickness becomes non-monotonic at intermediate head clearance during writing. Our data suggest that this complexity is caused by the interlayer thickness effects on the write field angle and gradient.