• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.444-450
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• 2000

We prepared Co-Cr thin film for perpendicular magnetic recording media with facing targets sputtering system(FTS system) which can deposit a high quality thin film in plasma-free state and wide range of working pressure. The effect of sputtering conditions(argon gas pressure and substrate temperature) on the magnetic and the crystallographic characteristic of Co-Cr thin film was investigated. And the variation of perpendicular coercivity with the variation of film thickness was studied. As a result we obtained the high perpendicular coercivity of 1900Oe and the good dispersion angle of c-axis($\Delta$$\theta$$_{50}$) of 5$^{\circ}$on the film thickness of 100nm for the promising recording layer of perpendicular magnetic recording media.c recording media.a.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.16-27
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• 2015

Holography technology which was developed by Dennis Gabor (1900~1979) in 1948 is a technology to record wave planes of actual 3D objects. It is known as the only technology which can express 3D information most perfectly close to human-friendly. Holography technology is widely used in advertisement, architecture and arts as well as science technology areas. Especially, digital holographic print which is an applied area is greatly used in military map, architecture map and cultural asset restoration by printing and reproducing 3D information. Holography is realized by recording and reproducing the amplitude and phase information on high resolution film using coherent light like laser. Recording materials for digital holographic printer are silver halide, photoresist and photopolymer. Because the materials have different diffraction efficiency according to film characteristics of each manufacturer, appropriate guide lines should be suggested through efficiency analysis of each film. This paper suggests appropriate guide lines through the diffraction efficiency measurement of silver halide which is a holographic printer recording medium. And the objective of this study is to suggest appropriate guide lines through diffraction efficiency analysis of Ultimate 08-C and PFG-03C which are commercially used. The experiment was prepared by self-diffraction efficiency system which measures the strength with the defector by penetrating RGB recording medium and concentrating diffracted beams through collimating lens. The experiment showed Geola's PFG-03C which is a silver halide for full color has price/performance advantage in optical hologram recording, but recording angles and reproduction angles are irregular for digital holographic printer recording. Ultimate's Ultimate08-C for full color shows its diffraction efficiency is relatively stable and high according to recording angles and laser wavelength.

• Proceedings of the Korean Magnestics Society Conference
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• 1999.10a
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• pp.28-29
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• 1999

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.77-80
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• 2001

Crystallographic and magnetic characteristics of CoCr-based magnetic thin film for perpendicular magnetic recording media were influenced on preparing conditions. In these, there is that substrate temperature was parameter that increases perpendicular coercivity of CoCrTa magnetic layer using recording layer. While preparation of CoCr-based doublelayer, by optimizing substrate temperature, we expect to increase perpendicular anisotropy of CoCr magnetic layer and prepare ferromagnetic recording layer with a good quality by epitaxial growth. CoCrTa/Si doublelayer showed a good dispersion angle of c-axis orientation $\Delta$$\theta$$_{50}$ caused by inserting amorphous Si underlayer which prepared at underlayer substrate temperature 250C. Perpendicular coercivity was constant, in-plane coercivity was controlled a low value about 2000e. This result implied that Si underlayer could restrain growth of initial layer of CoCrTa thin film, which showed bad magnetic properties effectively without participating magnetization patterns of magnetic layer. In case of CoCrTa/Si that prepared with ultra thin underlayer, crystalline orientation of CoCrTa was improved rather underlayer thickness 1nm, it was expected that amorphous Si layer played a important role in not only underlayer but also seed layer.t also seed layer.r.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.20-22
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• 1997

In ours study, we investigated the various properties in Te-light doped $Sb_{85}$G $e_{15}$ thin films such as the change of reflectance and transmittance according to phase change from amorphous to crystalline states In all films the transmittance was decreased, but the reflectance was increased by annealing. Particularly, the reflectance between as- deposited state and annealed state showed the largest change in the T $e_{0.5}$($Sb_{85}$G $e_{15}$ )$_{99.5}$ thin film at 780nm, which was about 40% in as-deposited state and about 70% in annealed state. Therefore, it might be considered that the T $e_{0.5}$($Sb_{85}$G $e_{15}$ )$_{99.5}$ thin film is recording medium showing to a good optical properties if it is used to optical recording of the phase change type. change type.ype.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.305-309
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• 2010

Photopolymer films containing fluorescent anthracene polymer, polymethyleneanthracene (PMAn), were prepared with different concentrations of PMAn for holographic recording useful for security documents. The fluorescent photopolymer film showed enhanced fluorescent intensity due to the micro-separation which arose from grating formation and diffusion during photopolymerization. Experimental values of diffraction efficiency were well matched to the simulated values for photopolymers having different PMAn concentrations. Holography patterning was carried out using the fluorescent photopolymer under a photo-mask. A grating was confirmed using microscope techniques in the recorded area under the pattern. Importantly the recorded area showed enhanced fluorescence compared to the unrecorded part, allowing fluorescence patterns at micro scale along with the submicron grating pattern. The fluorescence pattern recorded on the photopolymer film provides additional readability of holographic reading and thus is useful for secure recording and reading of information.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.631-635
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• 1995

Longitudinal magnetic recording process of thin film media was simulated by the 2-D finite element method (FEM). To describe precisely the hysteresis behavior of thin film media, scalar Preisach model was used. In this paper, we discussed the formation of bit patterns and importance of modeling of minor loops in high density recording. The effects of the media coercivity and film thickness on the remanent magnetization and transition shape were investigated.

• Transactions of the Society of Information Storage Systems
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• v.3 no.4
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• pp.173-177
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• 2007

A photo-reactive methacrylate monomer having triazine as a core component was examined for photochromic diffractive image formation. Photochromic photopolymer films as a recording media contained a monomer mixture of triazine difunctional metharylate (DT) and ethylene glycol phenyl ether acrylate, binder polymer, photo initiator, and a photochromic spiro-oxazine dye. The content of photochromic dye was changed to examine the effect of photochromophore on diffraction efficiency and real holographic image formation. Holographic recording was performed on the photopolymer film by the combination of reference and probe beam. The diffraction efficiency of the photopolymer film in real-time measurement reached a maximum of $\sim90%$ within 30s. It was highly dependent on the photochromophore contents. After holographic recording, the color of the recorded area was changed under UV light (365 nm) and reversibly bleached to original color upon exposure to a visible light source. Films containing only photochromophore without monomer mixture were not reactive under the recording beam (491nm). Diffractive image formation and mechanism of the holographic recording in the presence of photochromophore will be presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.463-465
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• 2002

In order to increase perpendicular magnetic anisotropy of magnetic layer and prepare magnetic recording layer with a good quality by epitaxial growth between magnetic layer and, we prepared Co$\_$77/Cr$\_$20/Ta$_3$/Si doublelayer for perpendicular magnetic recording media which was promoted as next generation recording media on slide glass substrate. The thickness of magnetic layer and Underlayer were varied from 20 to 100 nm and 5 to 100 m, respectively. The surface morphology and crystal structure of the CoCrTa/Si film were examined with XRD and AFM. Prepared thin films showed improvement of dispersion angle of c-axis orientation Δ$\theta$$\_$50/ caused by inserting amorphous Si underlayer.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.172-172
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• 1994