• Journal of the Korean Magnetics Society
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• v.16 no.2
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• pp.149-156
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• 2006

The frequency of the recording current and the rotating speed of the recording media are Increase for the high densities in perpendicular magnetic recording system with high conductive pole tip head and soft magnetic under-layer. In the paper, the frequency Induced eddy current and velocity induced eddy currents are analyzed by non-linear 3-dimensional finite element analysis. It it turned out that the frequency induced eddy current decreases the amplitude of the recording fields, whereas the velocity induced eddy current only distorts the distribution of the recording fields in the recording media.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.578-581
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• 1999

The Co-Cr-Ta films are one of the most suitable candidates for perpendicular magnetic recording media. The facing targets sputtering(FTS) system has a advantage of preparing films over a wide range of working gas pressure on plasma-free substrates. In this study, we investigated the effect underlayers on the growths layers of Co-Cr-Ta recording layers. The Co-Cr-Ta/Ti(CoCr) double layers were deposited with sputter gas pressure$(P_N, 0.3-1mTorr)$ by using FTS apparatus at temperature of$40^{\circ}C~-300^{\circ}C$, respectively. Crystallographic and magnetic characteristics were evaluated by x-ray diffractometry(XRD) and vibrating sample magnetometer(VSM), respectively.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.115.1-115.1
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• 2007

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.888-892
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• 2004

It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/［Ni-Fe/si］ layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

• Journal of the Korean Magnetics Society
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• v.2 no.1
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• pp.50-55
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• 1992

Numerical method for analyzing the reading process in magnetic recording system is described. Hysteresis characteristics must be included in numerical analysis not only recording process but also reading process because of hysteretic behavior of recording media. Algorithm which is consisted of finite clement method for numerical analysis and Preisach model considered to be more appropriate method than Stoner-Wohlfarth model with spin curling mode for describing hysteresis characteristics is constructed. Equations to calculate waveform of reproduced voltage is proposed. Then, this is applied to perpendicular magnetic recording systems with pole type head and double layer media. Waveform of magnetic flux density and reproduced voltage induced in head coil is obtained. If the recording current increase in recording process, magnitude of reproduced voltage in reproducing process saturates. From this saturation curve, value of current which produce maximum voltage can be obtained.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.41.1-41.1
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• 2007

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.419-422
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• 1999

We prepared CoCr thin film for perpendicular magnetic recording media by facing targets sputtering system(FTS system) which can deposit a high quality thin films in plasma-free state and wide range of working pressure. In this study, we investigated that the effect of sputtering condition , that Argon gas pressure and substrate temperature, on magnetic and crystallographic characteristic of CoCr thin film as well as the variation perpendicular coercivity in changing of film's thickness. Crystallographic and magnetic characteristic of prepared thin films were evaluated by x-ray fractometry(XRD), vibrating sample magnetometer(VSM) and kerr hysteresis loop measurement.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.28-31
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• 1990

In perpendicular magnetic recording system, the magnetic recording and reproduction characteristics of isolated transition of magnetization is simulated in this paper. The recording system which is magneto-static system is analyzed using two-dimensional finite element method and the characteristics of hysteresis of recording media is considered. The results show that the optimizing current is exist in magnetic recording system.

• Journal of the Korean Magnetics Society
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• v.17 no.6
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• pp.221-225
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• 2007

The effects of $Ga^+$ ion irradiation on the magnetic properties of the $Co_{73}Pt_{27}-TiO_2$ perpendicular magnetic recording media were investigated. As $Ga^+$ ion dose increased from $1\times10^{15}ions/cm^2\;to\;30\times10^{15}ions/cm^2$, the perpendicular magnetic anisotropy was degraded and no longer observed above $20\times10^{15}ions/cm^2$ dose. The deterioration of the perpendicular magnetic anisotropy and ferromagnetic properties can be attributed to the concentration profile change due to Ga+ ion implantation. The magnetic islands of $70\times70nm^2\;and\;100\times100nm^2$ size were successfully fabricated with $Ga^+$ ion irradiation.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.6-8
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• 2002

In order to prepare magnetic recording layer with a good quality crystallographic characteristic. We prepared $Co_{77}Cr_{20}Ta_3$ layer for perpendicular magnetic recording media on slide glass substrate by Two-Step Methode. The thickness of magnetic layer was fixed 100 nm and buffer layer were varied from 10 to 50 nm, and input current was varied from 0.2[A] to 0.5[A]. The surface morphology and crystal orientation of the CoCrTa films were examined with XRD. Prepared thin films showed improvement of dispersion angle of c-axis orientation ${\Delta}{\theta}_{50}$ caused by inserting buffer layer.