• Journal of the Korean Magnetics Society
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• v.3 no.4
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• pp.293-297
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• 1993

Exchange coupled $NiFe/TbCo/Sio_{2}$ thin films for magnetoresistive heads were sputter deposited using RF diode sputtering method, and their magnetic characteristics were measured. TbCo films were deposited using a composite target, which is composed of Tb chips epoxied on a Co target. NiFe($400\AA$)/TbCo($1500\AA$)/$SiO_{2}$($500\AA$) films were deposited using a TbCo target having 30 % of Tb area ratio, which showed 25 Oe of the exchange field without substrate bias and 12 Oe with -55 V of substrate bias. The effective in-plane coercivities of the three layer films fabricated with less than -55 V of substrate bias were approximately proportional to the perpendicular coercivities of the TbCo layer only. The films fabricated with a Theo target of 28 % area ratio showed the same trend. However, the exchange field decreased to 4 Oe without the substrate bias and 7 Oe with -55 V of substrate bias. In the films fabricated with 1000 W of power and the target of 36 % area ratio exhibited 100 Oe of exchange field and 3 Oe of coercivity. As the thickness of NiFe layer increased, the exchange field decreased.

• Korean Journal of Materials Research
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• v.23 no.3
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• pp.155-160
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• 2013

ZnO thin films co-doped with Mg and Ga (MxGyZzO, x + y + z = 1, x = 0.05, y = 0.02 and z = 0.93) were prepared on glass substrates by RF magnetron sputtering with different sputtering powers ranging from 100W to 200W at a substrate temperature of $350^{\circ}C$. The effects of the sputtering power on the structural, morphological, electrical, and optical properties of MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown as a hexagonal wurtzite phase with the preferred orientation on the c-axis without secondary phases such as MgO, $Ga_2O_3$, or $ZnGa_2O_4$. The intensity of the diffraction peak from the (0002) plane of the MGZO thin films was enhanced as the sputtering power increased. The (0002) peak positions of the MGZO thin films was shifted toward, a high diffraction angle as the sputtering power increased. Cross-sectional field emission scanning electron microscopy images of the MGZO thin films showed that all of these films had a columnar structure and their thickness increased with an increase in the sputtering power. MGZO thin film deposited at the sputtering power of 200W showed the best electrical characteristics in terms of the carrier concentration ($4.71{\times}10^{20}cm^{-3}$), charge carrier mobility ($10.2cm^2V^{-1}s^{-1}$) and a minimum resistivity ($1.3{\times}10^{-3}{\Omega}cm$). A UV-visible spectroscopy assessment showed that the MGZO thin films had high transmittance of more than 80 % in the visible region and that the absorption edges of MGZO thin films were very sharp and shifted toward the higher wavelength side, from 270 nm to 340 nm, with an increase in the sputtering power. The band-gap energy of MGZO thin films was widened from 3.74 eV to 3.92 eV with the change in the sputtering power.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1349_1350
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• 2009

Thin films of pp(ST-Co-VA) were fabricated by plasma deposition polymerization (PVDPM) technique. Properties of the plasma polymerized pp(ST-Co-VA) thin films were investigated for application to semiconductor device as insulator. Thickness, dielectric property, composition of the pp(ST-Co-VA) thin films were investigated considering the relationship with preparation condition such as gas pressure and deposition time. In order to verify the possibility of application to organic thin film transistor, a pentacene thin film was deposited on the pp(ST-Co-VA) insulator by vacuum thermal evaporation technique. Crystalline property of the pentacene thin film was investigated by XRD and SEM, FT-IR. Surface properties at the pp(ST-Co-VA)/pentacene interface was investigated by contact angle measurement. The pp(ST-Co-VA) thin film showed a high-k (k=4.6) and good interface characteristic with pentacene semiconducting layer, which indicates that it would be a promising material for organic thin film transistor (OTFT) application.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1477-1479
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• 2005

In this work, the ITO thin films were prepared by FTS (Facing Targets Sputtering) system under different sputtering conditions which were varying $O_2$ gas flow, input current at room temperature. As a function of sputtering conditions, electrical and optical properties of prepared ITO thin films were measured. The electrical, optical characteristics and surface roughness of prepared ITO thin films were measured. In the results, as increasing $O_2$ gas 0.1[sccm] to 0.7[sccm], resistivity of ITO thin film was increased with a decreasing carrier concentration, $O_2$ gas over 0.3[sccm] the carrier mobility have a similarly value. Transmittance of prepared ITO thin films were improved at increasing $O_2$ gas 0.1[sccm] to 0.7[sccm]. And transmittance of all of the prepared ITO thin films was over 80%. We could obtain resistivity $6.19{\times}10^{-4}[{\omega}{\cdot}cm]$, carrier mobility $22.9[cm^2/V{\cdot}sec]$, carrier concentration $4.41{\times}10^{20}[cm^{-3}]$ and transmittance over 80% of ITO thin film prepared at working pressure 1mTorr, input current 0.4A without any substrate heating.

• Journal of Magnetics
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• v.4 no.4
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• pp.119-122
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• 1999

Magnetic properties and crystal structures of (Fe1-XCoX) Pt (X = 0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0) ternary thin films were investigated. The order-disorder phase transformation of FePt thin films during annealing was also studied by x-ray diffraction and M ssbauer spectroscopy. The magnetic thin films were deposited on glass substrates using a dc sputtering method and were subsequently annealed at 400~$700^{\circ}C$ in a high vacuum. The as-deposited films exhibited a high degree of the <111> preferred orientation and the preferred orientation was not destroyed even after the subsequent post annealing. The coercivity of the ($Fe_xCo_{1-x}$) Pt thin films annealed at $700^{\circ}C$ showed a minimum value at the equiatomic composition of the Fe and Co atoms. The ordered structure of the FePt alloy was thought to have formed from the disordered structure by an inhomogeneous process, which was confirmed by the asymmetric peak shapes and M ssbauer spectra.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.190-191
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• 1994

In this paper, We study on the fabrication of amorphous this film of zeromagnetostriction material and the magnetic properties. This films are fabricated by using sputtering method with input power of 400∼607[W], Ar gas pressure of 3∼ 9[mTorr] and target composition of Fe$\sub$4.7/ Co$\sub$74.3/Si$_2$B$\sub$19/. Sample this films with diameter of 14[mm ] and thickness of 27-30[$\mu\textrm{m}$] were obtained through experiments. When we analyzed the magnetic properties before and after annealing with sample thin films, we confirmed that magnetic domain wall amorphous thin films consisted for Neel magnetic domain wall with the width of about 1[$\mu\textrm{m}$].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.231-232
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• 2007

Nickel oxide thin films were deposited by the DC magnetron reactive sputtering process under the conditions such as various oxygen flow rates(0, 3, 6, 8, 10 sccm) with constant 33 sccm argon flow rate for the sputtering time of 40 second with the power of 0.3 kW. Sheet resistances were measured by the four point probes. In order to observe discharge voltage characteristics according to the oxygen flow rates, the sputtering processes were performed under the powers of 0.2kW and 0.3kW. The feasibility of the coating system for high quality ferromagnetic thin films was tested through the electromagnetic simulation and the thin film thickness measurement from the experiment. It was shown that a discharge voltage was decreased under the low power and low oxygen flow rate, since the oxygen was quickly saturated on nickel target surface. The sheet resistance was increased as oxygen flow rate increased. The film thickness deposited by the coating system for ferromagnetic target was improved approximately 10% in comparison with previous coating systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.229-233
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• 2011

Diamond thin films were deposited on pretreated Co cemented tungsten carbide (WC-6%Co) inserts as substrate by microwave plasma chemical vapor deposition (MPCVD) system, equipped with a 915MHz, 30kW generator for generating a large-size plasma. The substrates were pretreated with two solutions Murakami solution $[KOH:K_3Fe(CN)_6:H_2O]$ and nitric solution $[HNO_3:H_2O]$ to etch, WC and Co at cemented carbide substrates, respectively. The deposition experiments were performed at an input power of 10 kW and in a total pressure of 100 torr. The influence of various $CH_4$ contents on the crystallinity and morphology of the diamond films deposited in MPCVD was investigated using scanning electron microscopy (SEM) and Raman spectroscopy. The diamond film synthesized by the $CH_4$ plasma shows a triangle-faceted (111) diamond. As $CH_4$ contents was increased, the thickness of diamond films increased and the faceted planes disappeared. Finally, Faceted diamond changed into nano-crystalline diamond with random crystallinity.

• Journal of Magnetics
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• v.11 no.4
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• pp.167-169
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• 2006

Nanocrystalline CoFeHfO thin films have been fabricated by RF sputtering method. It is shown that the CoFeHfO thin films possess not only high electrical resistivity but also large saturation magnetization and anisotropy field. Among the composition investigated, $Co_{53}FE_{22}Hf_{10}O_{15}$ thin film is observed to exhibit good soft magnetic properties: coercivity ($H_{c}$) of 0.18 Oe; anisotropy fild ($H_{k}$) of 49.92 Oe; saturation magnetization ($4{\Pi}M_{s}$) of 15.5 kG. The frequency response of permeability of the film is excellent. The excellent magnetic properties of this film in addition of an extremely high electrical resistivity (r) of $185\;{\mu}cm$ make it ideal for uses in high-frequency applications of micromagnetic devices. It is the formation of a peculiar microstructure that resulted in the superior properties of this film.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.337-345
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• 2000

The spontaneous Hall effect in amorphous Tb-Fe and Sm-Fe thin films, which possess excellent magnetic softness, is investigated in this work to seek a possibility of practical applications of these thin films as sensors. The resistivity of Tb-Fe thin films ranges from 180 to 250 Ωcm as the Tb content varies from 35 to 46 at. %. Tb-Fe thin films show negative Hall resistivity ranging from - 7.3 to - 5.0 Ωcm in the same composition range, giving the normalized resistivity ratio in the range of -4.1 to -2.0 %. On the other hand, the resistivity of Sm-Fe thin films ranges from 150 to 166 Ωcm as the Sm content varies from 22 to 31 at. %. Sm-Fe thin films show positive Hall resistivity which varies from 7.1 to 2.8 Ωcm in the same composition range, giving the normalized resistivity ratio in the range of 4.8 to 1.7 %. These values are significantly high compared with the values of other R-T alloys, Tb-Co alloys for example, where the highest reported value is 2.5 %. Between the two different sets of samples, Tb-Fe thin films with perpendicular anisotropy are considered to be more suitable for practical applications, since saturation is reached at a los magnetic field, approximately 2 kOe in a Tb$\sub$35.1/ Fe$\sub$64.9/ thin film, for example.