• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.506-507
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2016.05a
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• pp.95-96
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• 2016

• Journal of the Korean Magnetics Society
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• v.8 no.1
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• pp.21-26
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• 1998

The temperature dependence of the magnetoimpedance (MI) effect is important both for scientific study and for thermal stability of MI sensor. We have performed the measurement of MI effect in amorphous $Co_{66}Fe_1Ni_1B_{14}Si_{15}$ (Metglas 2714 A) ribbon from a cryogenic chamber where the temperature of the sample can vary from 10 K to 300 K. The ac current was fixed at 10 mA for all measured frequencies ranging from 100 KHz to 10 MHz. The magnetoimpedance ratio (MIR) was revealed the drastic increment as a function of MIR (T) = MIR (0) exp(cT$^2$) where c is a constant. The measured MIR values at room temperature are usually 2-3 times larger than the data measured at 10 K for all measured frequencies. However, the shapes of the MIR curves are remained. This result shows the potential application of the MI effect for a temperature sensor. The frequency dependence of MIR has shown the typical tendency where the maximum values of MIR are increasing ans also the shapes of MIR curves are getting broader as the measured frequency increases.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.91-98
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• 1992

In a $Co_{67}Fe_{4.5}Nb_{2}Si_{10}B_{15}$ amorphous alloy ribbon the effect to two-step annealing on the soft magnetic properties has been studied. By two-step annealing method which the second annealing at low temperature of $310^{\circ}C$ for 2 hours is undertaken after the primary annealing at high temperature above $480^{\circ}C$ for 20 minutes at the vacuum state, the coercive force and the squareness are not changed nearly but the initial permeability at d.c. and the effective permeability at a.c. are remark-ably increased compared with the one-step annealing. The maxima of the initial permeability and the effective permeability at 1 kHz after the two-step annealing are 290,000 and 41,000, respectively, which are 30% higher than those of the one-step annealing. The change of magnetic properties with annealing temperature is discussed in terms of the residual stress, the domain size, the cluster and the crystalline phase.

• 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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• 1994.05a
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• pp.149-151
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• 1994

This thesis describes the effect of heat treatment on the magnetic properties of Co-bsaed Amorphous. A sample was chosen as basic composition with Co$\_$82//Si$\_$2//B$\_$16/ of zero magnetostriction. It was made by single roll method with quartz orifice 0.5[mmø], Ar gas pressure 0.6 [kg/cm$^2$] and roll speed 28 (m/sec) and atmosphere is ,Ar gas. We obtained the sample of width 2.4(mm), thickness 45[$\mu\textrm{m}$]. Made sample annealed for the improvement of magnetic propertics at at annealing temperature 325,350,375 and 400$^{\circ}C$ and annealing time 15, 30, 45, 60 and 120min respectiveily. Amorphous ribbon of co-based showed high permeab- ility ${\mu}$=8000∼14000, and became improvement of magnetic properties according to anneal ins temperature and time. Especially. Amorphous sample at 325$^{\circ}C$ ,45min appearanced high permeability ${\mu}$=13, 589 at frequency f= 100Hz. and loss factor was reduced at low frequency with rising anneal ins ti me and temperature more annealed sample than basic sample.

• Korean Journal of Materials Research
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• v.7 no.9
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• pp.728-732
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• 1997

비정질 금속 $Co_{66}$F $e_{4}$Ni $B_{14}$S $i_{15}$ 의 표면층 제거에 대한 자기임피턴스 효과는 시료의 길이방향에 평행한 일축자기장에 대하여 측정하였다. MIR(Magnetoimpedance Ratios)은 비정질 금속의 두께가 얇아짐에 따라 감소하고, 전류에 비례하여 증가하는 경향을 나타내었다. 인가전류 주파수에 대한 MIR과 자기장의 감도는 모든 시료에서 주파수에 비례하여 증가하며 수 MHz 부근에서 최대값을 가지고 점차 감소하는 경향을 나타내었다. 시료의 표면층제거에 기인한 이방성자기장의 변화는 MI $R_{Max}$을 나타내는 외부 자기장을 감소시키지만, MIR은 표면층 제거에 따른 부피효과에 기인하여 감소하였다....

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.503-509
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• 2001

Thin films of hydrogenated amorphous silicon (a-Si : H) and hydrogenated amorphous silicon carbide (a-SiC:H) of different compositions were deposited on Si(100) wafer and glass by RF plasma-enhanced chemical vapor deposition (RF-PECVD). In the present work, we have investigated the effects of the RF power on the properties, such as optical band gap, transmittance and crystallinity. The Raman data show that the a-Si:H material consists of an amorphous and crystalline phase for the co-presence of two peaks centered at 480 and $520 cm^{-1}$ . The UV-VIS data suggested that the optical energy band gap ($E_{g}$ ) is not changed effectively with RF power and the obtained $E_{g}$(1.80eV) of the $\mu$c-Si:H thin film has almost the same value of a-Si:H thin film (1.75eV), indicating that the crystallity of hydrogenated amorphous silicon thin film can mainly not affected to their optical properties. However, the experimental results have shown that$ E_{g}$ of the a-SiC:H thin films changed little on the annealing temperature while $E_{g}$ increased with the RF power. The Raman spectrum of the a-SiC:H thin films annealed at high temperatures showed that graphitization of carbon clusters and microcrystalline silicon occurs.

• Journal of the Korean institute of surface engineering
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• v.50 no.3
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• pp.177-182
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• 2017

The properties of electroless Ni-B thin film on diamond powder with different parameters (temperature, pH, surfactant etc.) were studied. The surface morphology, structure and composition distribution of the Ni-B film were observed by field effect scanning electron microscope (FE-SEM), energy-dispersive spectrometer (EDS), X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The growth rate of Ni-B film was increased with increase of bath temperature. The B content in Ni-B film was reduced with increase of bath pH. As a result the structure of Ni-B film was changed from amorphous to crystalline structure. The PVP in solution plays multi-functional roles as a dispersant and a stabilizer. The Ni-B film deposited with adding 0.1 mM-PVP was strongly introduced an amorphous structure with higher B content (25 at.%). Also the crystallite size of Ni-B film was reduced from 12.7 nm to 5.4 nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.27-30
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• 1996

In this paper, we prove through the experiments the possibility that Co-amorphous magnetic films can be used as high sensibility materials. We fabricate amorphous film of Fe$\sub$4.7/Co$\sub$74.3/Si$_2$B$\sub$19/ by using sputtering method at high frequency. Then, we not only measure the magnetic Properties of the annealed samples, but also observe the magnetic domain by using an Kerr effect optical-microscope. As the result, we find that the samples have high sensibility