Development of Dual Track Complimentary type recording heads and its Application to High Density Perpendicular Magnetic Recording System

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We proposed the dual track complimentary type of thin film recording head as a new concept to improve the efficiency of the read/write characteristics in perpendicular magnetic recording system. Since the proposed head has a magnetic core layr with its shape of character 'U', closed circuit of magnetic flux will be attained in the recording system. In order to realize the thin film heads, we have to investigate a soft magnetic thin film for a core layr of the heads, magneto-resistive heads with good soft magnetism for read out system of recorded signal and micro-fabrication technology, such as lithography techniques, for fabrication of thin film heads. For soft magnetic layrs, Fe_xN films prepared by Ion Beam Deposition method, which is investigated by the authors, revealed a soft magnetism with sufficiently large saturation magnetization 4piM_s of about 19 kG, coercivity H_c as low as about 1.0 Oe and relative permeability mu_r of as large as 1000. These results were regarded as sufficient for magnetic core layrs of the new type thin film heads. Although the giant magneto-resistivity observed in the multilayrrs composed of magnetic and non-magnetic metal layrs were very attractive for the application of the MR heads, the magnetic field sensitivity of them is too low to apply them to MR heads. We have investigate that the Ni-Fe/Cu multilayrs prepared by Ion Beam Sputtering technique exhibit relatively large MR ratio of about 16% at room temperature and the multilayr has an relatively soft magnetism, that is, low H_c of about 5 Oe and high mu_r of about 500. It was investigated that the field sensitivity DELTAMR/DELTAH of the multilayrs were controrable by ajusting the crystallites orientation of Fe-buffer layrs. (100) orientation of crystallites in Fe-buffer layrs enhance the (100) orientation of fcc crystallites in Ni-Fe/Cu multilayrs because of a heteroepitaxial effect. Ni-Fe/Cu multilayrs deposited on (100) oriented Fe-b