• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.475-478
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• 2005

Permalloys were successfully fabricated by melt drag casting in the present study, and their variation of microstructure and consequent magnetic properties were investigated as a function of Si contents and annealing temperature. The increases in Si content and annealing temperature resulted in the increases of grain size and amount of $Ni_3Fe$ ordered phase. Both the grain size and $Ni_3Fe$ ordered phase controlled by Si and annealing temperature had a important role on permeability of permalloys.

• 한국자기학회지
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• 제8권1호
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• pp.13-20
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• 1998

초미세결정립과 비정질을 동시에 포함하는 리본형 Fe73.9Cu1.0Nb3.5Si14.0B7.6 합금을 자기장 중 열처리한 시편의 결정？적 특성 및 고주파 연기자 특성을 인가 자기장과 열처리 온도에 따라하여 조사아였다. 제조된 리본의 표면에 석출된 Fe-Si 초미세결정립은 (400) 우선방위를 나타내는 동시에 리본길이방향으로 [011] 결정측이 형성되어 있음을 확인하엿다. 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리할 때 45$0^{\circ}C$에소 Fe-Si 초미세결정립이 석출되다, 폭방향의 자기장을 인가한 경우 초미세결정립의 석출은 지연되어 55$0^{\circ}C$에서 나타남을 확인하였다. 길이방향으로 자기장을 인가할 때 시편의 결정화 정도는 외부 자기장을 인가하지 않은 경우에 비해 조금 증가하였다. 그러나, 시편의 각도를 기울여 측정된 X-선 회절패턴으로부터 시편내부는 표면과 달리 결정화가 진행되고 있음을 확인하였다. 열처리한 시편의 포화자기유도는 1.3T로 비슷하였다. 열처리전 리본의 보자력의 크기는 1.06A/츠이었으나, 열처리한 시편은 열처리 온도가 40$0^{\circ}C$에서 55$0^{\circ}C$로 증가함에 따라 0.56A/cm에서 0.1A/cm로 감소하였다. 폭방향의 자기장을 인가한 경우 각형비는 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리한 시편의 각형비보다 작았다.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2279-2282
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• 2007

Highly crystalline, uniform Fe nanoparticles were successfully synthesized and encapsulated in zirconia shell using sol-gel process. Two different approaches have been employed for the coating of Fe nanoparticle with zirconia. The thickness of zirconia shell can be readily controlled by altering molar ratio of Fe nanoparticle core to zirconia precursor in the first case where as reaction time was found to be most effective parameter to controlled the shell thickness in the second method. The structure and magnetic properties of the ZrO2-coated Fe nanoparticles were studied. TEM and HRTEM images show a typical core/shell structure in which spherical α-iron crystal sized of ~25 nm is surrounded by amorphous ZrO2 coating layer. TGA study showed an evidence of weight loss of less than 2% over the temperature range of 50-500 °C. The nanoparticles are basically in ferromagnetic state and their magnetic properties depend strongly on annealing temperature. The thermal treatment carried out in as-prepared sample resulted in reduction of coercivity and an increase in saturation magnetization. X-ray diffraction experiments on the samples after annealing at 400-600 °C indicate that the size of the Fe@ZrO2 particles is increased slightly with increasing annealing temperature, indicating the ZrO2 coating layer is effective to interrupt growing of iron particle according to heat treatment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.81-84
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• 2004

The NiCr is an important material for present thin-film resistor application owing to its low TCR and thermal stability. In this work, the NiCr thin films were deposited on coming glass substrate by reactive magnetron sputtering and the annealing at temperatures range from 300 to $500^{\circ}C$ for 20 min in vacuum. X-ray, AFM, $R_s$(surface leakage current) have been used to study the structural and electrical properties of the NiCr thin films. The high precision NiCr thin films resistor with TCR(temperature coefficient of resistance) of less then $10\;ppm/^{\circ}C$ was obtained under in in-situ annealing at $300^{\circ}C$ on Cr buffer layer substrate. It is clear that the NiCr thin-films resistor electrical properties are low TCR related with it's annealing and buffer layer condition. NiCr thin film resistor having a good thermal stability and low TCR properties are expected for the application to the dielectric material of passive component.

• Macromolecular Research
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• 제14권1호
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• pp.38-44
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• 2006

Vacuum deposited copper phthalocyanine (CuPc) was placed as a thin interlayer between indium tin oxide (ITO) electrode and a hole transporting layer (HTL) in a multi-layered, organic, light-emitting diode (OLEOs). The well-stacked CuPc layer increased the stability and efficiency of the devices. Thermal annealing after CuPc deposition and magnetic field treatment during CuPc deposition were performed to obtain a stacked-CuPc layer; the former increased the stacking density of the CuPc molecules and the alignment of the CuPc film. Thermal annealing at about 100$^{circ}C$ increased the current flow through the CuPc layer by over 25$\%$. Surface roughness decreased from 4.12 to 3.65 nm and spikes were lowered at the film surface as well. However, magnetic field treatment during deposition was less effective than thermal treatment. Eventually, a higher luminescence at a given voltage was obtained when a thermally-annealed CuPc layer was placed in the present, multi-layered, ITO/CuPc/NPD/Alq3/LiF/AI devices. Thermal annealing at about 100$^{circ}C$ for 3 h produced the most efficient, multi-layered EL devices in the present study.

• 한국자기학회지
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• 제7권4호
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• pp.180-185
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• 1997

비정질 리본으로 제조된 링 코아 시편의 자장중 열처리 조건에 따른 철손 및 보자력 등의 연자기 특성 변화를 BH loop tracer를 이용하여 최대인가자기유도 0.1 T를 유지하면서 10 kHz에서 측정하였다. 열처리 시간이 증가함에 따라 코아의 철손 및 보자력은 감소하여 최소값에 도달한 다음 다시 증가한다. 공기 중에서 열처리한 경우의 시료가 Ar 분위기에서 열처리한 시료 보다 우수한 연자기 특성을 나타낸다. 코아의 원주방향으로 자장을 인가한 경우에는 인가자장의 세기가 6 Oe 이상이어야 자장중 열처리 효과가 나타나 철손 및 보자력이 감소하였으며, 냉각시 Curie 온도근처에서의 냉각속도가 빠를 수록 철손과 보자력은 감소한다. 코아의 폭 방향으로 자장을 인가한 경우에는 보자력의 증가와 투자율의 감소 및 약간의 철손 증가가 나타났다.

• 한국결정성장학회지
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• 제17권1호
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• pp.11-17
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• 2007

The spherical NiZn ferrite particles were prepared by ultrasonic spray pyrolysis with mixed solution of aqueous metal nitrates. The NiZn ferrite particle was observed with nano-sized primary particles of about 10 nm or less before annealing which represented as paramagnetic behavior measured at 77 K and room temperature. The typical abnormal growth of primary particles like polyhedral primary particles was observed by annealing at 1273 K with Zn-concentration dependency. The XRD patterns showed good crystallinity of NiZn ferrite powder after annealing. In annealing process, the intra-particle sintering phenomenon was observed and the spherical particle morphology was collapsed at 1673 K. The saturation magnetization of NiZn ferrite powder for each annealing temperature was decreased with measuring temperature of $77{\sim}$300K.

• Journal of Magnetics
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• 제11권3호
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• pp.111-114
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• 2006

We electroplated copper-cobalt thin films on a silicon substrate, which had 150 nm thick copper seed layer. The adhesion between the two metallic layers could be increased by utilizing a proper organic additive, pulse plating technique, and high temperature annealing. The thin films exhibited columnar growth of the deposits and enhanced adhesion. This is attributed to the grain growth mechanism introduced by the additive and annealing.

• 한국입자에어로졸학회지
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• 제6권1호
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• pp.21-27
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• 2010

New process consisting of electrospray and epitaxial crystal growth processes was applied to the preparation of c-plane oriented barium ferrite ($BaFe_{12}O_{19}$) thin film for high density magnetic recording media. Sodium citrate aided process was proper to preparation of amorphous $BaFe_{12}O_{19}$ nanoparticles with geometric mean diameter of 3 nm and geometric standard deviation of 1.1. The electrospray was applicable to the prepare of amorphous $BaFe_{12}O_{19}$ thin film on a substrate, and the film thickness could be controlled by adjusting the electrospray deposition time. The c-plane oriented $BaFe_{12}O_{19}$ thin film was successfully prepared by 3 step annealing process of the $BaFe_{12}O_{19}$ amorphous film on a sapphire($Al_2O_3$) substrate; annealing at $350^{\circ}C$ for 30 min, annealing at $500^{\circ}C$ for 30 min, and annealing at $700^{\circ}C$ for 60 min.

• Journal of Magnetics
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• 제10권4호
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• pp.145-148
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• 2005

Effect of vacuum annealing on the microstructures and magnetic properties of $Fe_{84}Si_6B_{10}$ films has been investigated as a function of annealing temperature. X-ray diffraction and transmission electron microscopy were employed to analyze crystallization behavior of the films. Permeability of the films was measured at various frequencies by one-turn coil method. When the films were annealed below 673 K, the coercivity of the films did not change a lot (${\~}$1500 A/m) although the grain size of a crystalline phase in the partially crystallized films increased gradually up to about 16 nm. It then increased rapidly as the films became almost fully crystalline mostly with $\alpha$-(Fe,Si) phase at and above 723 K. On the other hand, the electrical resistivity of the films decreased monotonically with the increase of annealing temperature. The permeabilities of the films annealed at 473${\~}$673 K were all over 1000, showing the optimum value of 3500 at 523 K, and almost constant up to 300 MHz. However, those of the as-deposited and fully crystallized films were lower than 1000 and unstable at the same frequency range.