HIGH-FREQUENCY CHARACTERIZATION AND RECORDING PERFORMANCE OF NIFE ANDLAMINATED FEN HEADS

A simple high frequency characterization technique extended from DC di sk erasure is presented to measure the write field degradation for fre quencies up to 500 Mfc/s (250 MHz) on plated NiFe and sputtered lamina ted FeN heads. The results show that eddy currents appear to be the ma in cause for high frequency write field degradation. Overwrite recordi ng measurements, which may be used to approximate the non-linear write effects, also indicate that FeN heads, despite low efficiency, may be adequate for writing up to 100 MHz on a disk with a coercivity of 250 0 Oe. This disk is capable of supporting 5-10 Gb/in(2) densities.