• Journal of the Korean Magnetics Society
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• v.12 no.5
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• pp.174-178
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• 2002

Ac magnetic field was changed in the vicinity of a flaw because of the distribution of eddy current within a conductor, when the magnetic field was applied to a conductor having a flaw. The flaw detection was performed by using Co-based amorphous wire sensor head. The wire has almost 0 magneto-striction and high permeability. An comparative uniform magnetic field was applied to a 1㎜ thick copper plate and a 25㎛ thick aluminum sheet conductor using spiral typed coil. The size of the coil has 40㎜$\times$40㎜ outer width and 8㎜$\times$8㎜ inner width. The copper plate and the aluminum sheet has 0.5㎜ and 0.1㎜ wide gap, respectively. The frequency range of applied field was 100㎑∼600㎑. The induced voltage difference of 2.5㎷ was obtained in the maximum voltage and minimum one measured across the gap of the 1mm thick conductor. In the case of aluminum sheet, 0.4㎷ was obtained. From this results, the effectiveness of Co-based amorphous wire was confirmed in the ECT technique.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.276-278
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• 2006

The switching characteristics of magnetic tunnel junctions (MTJs) comprising amorphous ferromagnetic CoFeSiB free layer have been investigated. CoFeSiB was used for the free layer to enhance the switching characteristics. The typical junction structure was $Si/SiO_{2}/Ta$ 45/Ru 9.5/IrMn 10/CoFe $7/AlO_{x}/CoFeSiB\;(t)/Ru\;60\;(in\;nm)$. CoFeSiB has low saturation magnetization ($M_{s}$) of $560\;emu/cm^{3}$ and high anisotropy constant ($K_{u}$) of $2800\;erg/cm^{3}$. These properties caused low coercivity ($H_{c}$) and high sensitivity in MTJs, and it also confirmed in submicrometer-sized elements by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. By increasing CoFeSiB free layer thickness, the switching characteristics became worse due to increase of the demagnetization field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.281-286
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• 2002

In odder to investigate the magnetic properties of CoCr-based bilayered thin films on kind of underlayer, we introduced amorphous Si layer to Co-Cr(-Ta) magnetic layer as underlayer. First, we prepared CoCr and CoCrTa single layer using the Facing Targets Sputtering system to investigate theirs properties. It was revealed that with increasing the film thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. The CoCrTa thin film showed bettor crystalline and magnetic characteristics than CoCr thin film. As a result of investigating magnetic properties of CoCr and CoCrTa magnetic layer on introducing the Si underlayer, perpendicular coercivity and saturation magnetization of CoCr/Si and CoCrTa/Si bilayered thin film were decreased due to the increased grain size and diffusion of Si atoms to magnetic layer. And they showed constant with increasing the film thickness of Si thin film. However, in case of CoCrTa/Si bilayered thin film, in-plane coercivity was controlled low at about 250Oe. The c-axis orientations of CoCr/si and CoCrTa/Si bilayered thin film showed a good crystalline characteristics as about $2^{\circ}$.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.20-20
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• 1996

• Proceedings of the Korean Magnestics Society Conference
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• 1994.03a
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• pp.38-39
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• 1994

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.502-503
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2016.05a
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• pp.80-80
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• 2016

• Proceedings of the Korean Magnestics Society Conference
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• 2016.11a
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• pp.60-61
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• 2016

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4005-4010
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• 2011

We investigated thermal behavior of spin-coated films of P(HB-co-HHx)/PEG blends by using infraredreflection absorption (IRRAS) spectroscopy and 2D correlation spectroscopy. Based on 2D IRRAS correlation spectra, we could determine the sequence of spectral intensity changes with increasing temperature that PEG band changes first and then a band for crystalline component of P(HB-co-HHx) changes before a band for amorphous component. The intensities of bands for PEG and amorphous P(HB-co-HHx) were changed greatly as PEG weigh % of P(HB-co-HHx)/PEG blends increased. Transition temperatures of P(HB-co-HHx)/PEG blends were successfully determined by 2D gradient mapping method. The transition temperature of spincoated films of 98/2 and 90/10 P(HB-co-HHx)/PEG blends and 80/20 P(HB-co-HHx)/PEG blend determined by 2D gradient map are, respectively, about 137.5 and $132.5^{\circ}C$. Furthermore, P(HB-co-HHx)/PEG blends show an additional transition temperature that have been interpreted in terms of different lamellar thicknesses in spin coated films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.276-283
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• 2005

Magnetic tunneling transistor (MTT) device using the amorphous n-type Si semiconductor film for base and collector consisting of the [CoFe/NiFe](free layer) and Si(top layer) multilayers was used to study the spin-dependent hot electron magnetocurrent (MC) and tunneling magnetoresistance (TMR) at room temperature. A large MC of 40.2 % was observed at the emitter-base bias voltage ( $V_{EB}$ ) of 0.62 V. The increasing emitter hot current and transfer ratio ( $I_{C}$/ $I_{E}$) as $V_{EB}$ are mainly due to a rapid increase of the number of conduction band states in the Si collector. However, above the $V_{EB}$ of 0.62 V, the rapid decrease of MC was observed in amorphous Si-based MTT because of hot electron spin-dependent elastic scattering across CoFe/Si interfaces.