A magnetic head for 150 MHz, high density recording

A multilayered magnetic head that can read and write at 150 MHz on metal particle tape with a coercivity of 120 kA/m (1500 Oe) has been developed. Ten 2- mu m layers of Fe/sub 68/Ru/sub 8/Ga/sub 7/Si/sub 17/ alloy, with 100 nm of SiO/sub 2/ used as spacer, form the magnetic-core thickness and the track width. The head was tested in a rotary recording system at a relative head-to-tape speed of 73 m/s. At a linear density of 4000 fc/mm (100 kfc) and 150 MHz, the measured single frequency signal to 300-kHz-slot noise was 33 dB (RMS-RMS). The measured frequency response curve agrees with theory and indicates a head-to-tape spacing of 70 nm at high speed. The read efficiency of the head decreases from 37% at low frequency to 15% at 150 MHz.<
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