We have already reported that the domain structures of soft-magnetic thin films can be simulated by using a program based on the Monte-Carlo method. However, there were differences between the simulated results and those obtained experimentally. Therefore we have analysed these differences. We simulated the dependence of domain structures upon the anisotropy and applied field and the response of the magnetic structure in an MR film to an applied field.

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Advances in operating systems and increased use of large multimedia files have caused a greater need for large capacity magnetic disk drives. The areal density, which directly affects the capacity, will increase to above 10 Gbit/in2 by the end of this century. This huge increases in areal density will require the breakthrough such as spin valve heads, low noise media, near-contact sliders and dual-stage actuator servo control. We have successfully demonstrated magnetic recording at an areal density of 5 Gb/in2 with narrow track NiFe/Co90Fe10 spin-valve read heads on low noise CoCrTaPt/CrMo alloy thin film disks and with other subsidiary technologies which must appear in 10 Gb/in2 recording.

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The stress configuration of SAL (soft adjacent layer)-biased magnetoresistive (MR) elements has been analyzed, in order to study the stress-induced anisotropy effect on the MR transfer characteristics. The stress analysis, on the basis of stress measurement results in the single-layer sheet films that formed the MR elements, shows that anisotropic tensile stress of around 100 to 300 MPa is induced in the element height direction in the SAL film with an open-pattern edge structure. Furthermore, we calculated the MR transfer curves using a micromagnetic model for samples with different saturation magnetostriction constant (λ_s) value for SAL films. Assuming anisotropic tensile stress of 300 MPa in the element height direction throughout the entire track region, a desirable λ_s value for SAL films is in the range from+1×10^<-6> to -2×10^<-6>, because the stress-induced anisotropy in the SAL does not seriously affect the MR transfer curves.

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A newly designed vertical magnetoresisteive(MR)/inductive head has been developed for high density rigid disk drive. In this new head, MR element has the tri-layer stracture, in which the insulator layer is sandwiched between the two permalloy layers, and ends of the elements are filled with insulator. The current lead is connected only to the upper NiFe layer. As a result, not only the sense current density is enlarged but also the film Hk is reduced. The sensor sensitivity is estimated to be 2.5 times as large as that of conventional vertical MR sensor. This head has potensial for recording densities up to 2.0Gb/in^2.

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It is required to have high recording density and high data transfer rate for the Digital VCR. For these performance, the magnetic heads used for them VCR are necessary to have superior reproduced output especially in high frequency region. In this paper, we have investigated laminated type heads with magneto-static coupled Co-based amorphous films with electrically isolated layers for improving head performance. Low temperature metal diffusion bonding method is used on this head.

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A four-layer laminated CoZrNb/SiO_2 film with isotropic magnetic properties has been investigated for application in a new type of submicron trackwidth thin film head. An easy axes orthogonally oriented film was constructed with two sets of uniaxial laminated films. The dual-axial anisotropy film exhibits an isotropic permeability over 2500 at 10 MHz. Dynamic magnetization observation by Scanning Kerr Effect Microscope suggests that the the dual-axial core exhibits a higher efficiency of flux propagation carrying efficiency than the uniaxial core does.

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In this paper, 8/10 MSN(Matched Spectral Null) coded PRML(Partial Response Maximum-Likelihood) system constructed by utilizing PR4ML system by write and read equalization is studied. And the relation of the required readback SNR to achieve a bit error rate of 10^<-4> versus the normalized linear density obtained by computer simulation is compared with that of conventional 8/10 MSN coded PRML system. The result shows that our system has an excellent performance in high density recording.

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An application of the neural network equlization to the partial response maximum-likelihood(PRML) channel with partial erasure is studied. First, a model of the recording/reproducing channel with partial erasure and a neural network equalizer are described. Then, the bit-error rates are obtained by computer simulation and the performance is compared with that of the conventional Nyquist equalization. The results show that the error rate performance of neural network equalization is better than that of Nyquist equalization.

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