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

为了提高垂直磁记录系统的读写效率，我们提出了双道互补型薄膜记录磁头的新概念。由于所提出的磁头具有U形的磁芯层，因此在记录系统中将实现磁通量的闭环。为了实现薄膜磁头，我们必须研究软磁薄膜作为磁头的芯层、软磁良好的磁阻磁头用于记录信号的读出系统和微加工技术，如光刻技术，以制造薄膜磁头。对于软磁层，作者研究了离子束沉积法制备的Fe_xN薄膜具有足够大的饱和磁化强度4piM_s约19 kG，矫顽力H_c低至约1.0 Oe，相对磁导率mu_r大至1000的软磁特性。这些结果对于新型薄膜磁头的磁芯层是足够的。由磁性和非磁性金属层组成的多层磁阻器虽然对磁头的应用具有很大的吸引力，但其磁场灵敏度太低，无法应用于磁头。我们研究了离子束溅射技术制备的Ni-Fe/Cu多层膜在室温下具有较大的磁流变率（MR），约为16%，并且多层膜具有较软的磁性，即低H_c约为5 Oe，高mu_r约为500。研究了通过调整铁缓冲层的晶体取向可以控制多层膜的场灵敏度DELTAMR/DELTAH。由于异质外延效应，fe缓冲层中晶体的（100）取向增强了Ni-Fe/Cu多层中fcc晶体的（100）取向。Ni-Fe/Cu多层沉积在（100）取向的Fe-b上

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