LONGITUDINAL KERR-EFFECT ENHANCEMENT OF A 384 TRACK HEAD FOR HIGH DATA RATE READOUT

In a multitrack readout device, a transducer using the longitudinal Ke rr effect performs a high data rate and high resolution playback of a conventional magnetic tape. The magneto-optical transducer is describe d. The enhancement of the transducer figure of merit and efficiency in order to improve its data rate performance is discussed. The thicknes ses of the magnetic and gap layers are deduced from a matrix calculati on and give a factor of merit enhanced up to 3.9 X 10(-3). The soft ma gnetic properties of a very thin (30 nm) Sendust layer are carefully c ontrolled (Hc = 2 Oe) and allow to achieve experimentally a transducer efficiency of 30% at 50 kBPI. This head efficiency and the enhanced f igure of merit allow the magnetic tape readout at 500 Mb/s using a low cost light source.