• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.302.2-302.2
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.76-77
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• 2002

최근 거대자기저항(Giant magneto resistance)과 성질상으로 닮고 spin-valve와 같은 작용을 하는 ferromagnet(FM)/semiconductor, magnetic semiconductor(MS)/semiconductor 등의 다층막이 만들어지고 있으며, 비자성반도체에 spin-injection을 통한 spin-dependent electronic devices의 제작을 위한 연구가 활발히 진행중이다. 이처럼 III-FM-V, II-FM-Ⅵ, IV-FM 구조의 자성반도체(Magnetic semiconductor)에 대한 연구는 자기적 요소에 기반을 둔 반도체로의 적용가능성을 보임으로 많은 주목을 끌고 있다. 우리가 선택한 MnGe이 다른 자성반도체에 대해 상대적으로 가지는 이점은 다음과 같다. (중략)

• Proceedings of the Korean Magnestics Society Conference
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• 2002.04a
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• pp.98-99
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• 2002

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.143-147
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• 2001

Ferromagnetism in manganese compound semiconductors open prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds. Also it addresses a question about the origin of the magnetic interactions that lead to a Curie temperature(Tc) as high as 110 K for a manganese concentration of just 5%. Zener's model of ferromagnetism, originally suggested for transition metals in 1950, can explain Tc of $Ga_{1-x}Mn_x$ As and that of its IT-VI counterpart $Zn_{1-x}Mn_x$ Te and is used to predict materials with Tc exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin. In this article, we present not only the experimental result but calculated Curie temperature by RKKY interaction. The problem in making III-V semiconductor has been the low solubility of magnetic elements, such as manganese, in the compound, since the magnetic effects are roughly proportional to the concentration of the magnetic ions. Low solubility of magnetic elements was overcome by low-temperature nonequilibrium MBE{molecular beam epitaxy) growth, and ferromagnetic (Ga,Mn)As was realized. Magnetotransport measurements revealed that the magnetic transition temperature can be as high as 110 K for a small manganese concentration.

• 전자공학회논문지 IE
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• v.45 no.3
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• pp.1-4
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• 2008

We investigate magnetic semiconductor thin films for application towards spintronics, which can overcome current limitations in semiconductor devices. GaMnAs magnetic semiconducting films studied are easily integrated into conventional semiconductor processes and also offer a wide range of application, therefore it shows much promise as a future material. However the Curie temperature at which magnetic properties exist for GnMnAs is very low, also depending on deposition conditions the properties of the film can vary widely. In order to study these issues we investigate the best possible deposition conditions for magnetic properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.332.1-332.1
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• 2016

Application of magnetic fields is important to characterize the carrier dynamics in semiconductor quantum structures. We performed photoluminescence (PL) measurements from an InGaP-AlInGaP single quantum well under pulsed magnetic fields to 50 T. The zero field interband PL transition energy matches well with the self-consistent Poisson-Schr?dinger equation. We attempted to analyze the dimensionality of the quantum well by using the diamagnetic shift of the magnetoexciton. The real quantum well has finite thickness that causes the quasi-two-dimensional behavior of the exciton diamagnetic shift. The PL intensity diminishes with increasing magnetic field because of the exciton motion in the presence of magnetic field.

• Journal of the Korean Ceramic Society
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• v.55 no.6
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• pp.515-526
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• 2018

Cesium lead halide ($CsPbX_3$) nanocrystals have emerged as a new family of semiconductor nanomaterials that can outperform existing semiconductor nanocrystals owing to their superb optical and charge transport properties. Although these materials are expected to have many superior properties, control of the quantum confinement and isoelectronic magnetic doping, which can greatly enhance their optical, electronic, and magnetic properties, has faced significant challenges. These obstacles have hindered full utilization of the benefits that can be obtained by using $CsPbX_3$ nanocrystals exhibiting strong quantum confinement or coupling between exciton and magnetic dopants, which have been extensively explored in many other semiconductor quantum dots. Here, we review progress made during the past several years in tackling the issues of introducing controllable quantum confinement and doping of $Mn^{2+}$ ions as the prototypical magnetic dopant in colloidal $CsPbX_3$ nanocrystals.

• Journal of the Semiconductor & Display Technology
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• v.1 no.1
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• pp.35-40
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• 2002

Understanding of charging properties of a small particle is necessary to control the particle contamination and to improve productivity of the electronic device in the plasma aided semiconductor manufacturing processes. In this study, the effects of both magnetic field and particle size on the charging properties are experimentally investigated in collisional dusty plasmas. The experiments carried out in the system consisted of a monodisperse particle generation system, a DC magnetized plasma generation system and a charge measurement system. The plasma chamber is made of cross-shape Pyrex surrounded by magnetic bucket (composed of 12 permanent magnetic bar) to confine the plasma. DC magnetic field up to 250G are applied to the plasma zone by external magnetic coil. Previous work shows the charging effect clearly increase with increasing the size of the particle and plasma density, as it was expected.

• Journal of the Semiconductor & Display Technology
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• v.15 no.3
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• pp.30-34
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• 2016

We investigated magnetic field, discharged voltage, and as-deposited film uniformity at facing targets sputtering (FTS) system with magnetic field type: i) concentrated and ii) distributed magnetic field type. And Al doped ZnO (AZO) films were prepared at two magnetic field type such as concentrated magnetic field type and distributed magnetic field type, respectively. Discharge voltage at the distribution type is lower than concentration type due to low magnetic flux (middle magnetic flux: Concentration 1200 G and Distribution 600 G). The films deposited at the distributed magnetic field were more uniform than concentration type. All of prepared AZO films had a resistivity of under $10^{-4}[{\Omega}{\cdot}cm]$ and a transmittance of more than 85 % in the visible range.

• Journal of Magnetics
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• v.11 no.2
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• pp.83-86
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• 2006

Controlling magnetic domains in soft underlayer (SUL) of perpendicular magnetic recording (PMR) is an important issue for the application of PMR in HDD. We studied the magnetic domain structures in SUL using the finite element based micromagnetic simulation (FEMM) for the SUL models with different thicknesses. The purpose is to simulate the magnetic domain wall noise when the SUL thickness and saturation magnetization are changed. The simulation results show that a 15 nm SUL forms simpler Neel wall domain wall pattern and 40 nm SUL forms complex Bloch wall. To visualize the effect of these domain walls stray field at a read sensor position, the magnetic stray field of the domain walls at air bearing surface (ABS) which is 50 nm above the SUL was simulated and the results imply that Bloch walls have stronger stray field with more complicated field patterns than Neel walls and this becomes a significant noise source. Therefore, the thickness of the SUL should be controlled to avoid the formation of Bloch walls.