• Title/Summary/Keyword: Spin glass

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Organic TFT fabricated on ultra-thin flexible plastic with a rigid glass support

  • Son, Young-Rae;Han, Seung-Hoon;Lee, Sun-Hee;Lee, Ki-Jung;Choi, Min-Hee;Choo, Dong-Joon;Jang, Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.756-759
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    • 2007
  • We have fabricated pentacene OTFT on ultra-thin flexible polyimide film with a rigid glass support. Polyimide film of the thickness of $10{\mu}m$ has formed on glass by spin coating from the solution. After the entire OTFT process, the OTFT exhibited a fieldeffect mobility of $0.4\;cm^2/Vs$, an $I_{on}/I_{off}$ ratio of $10^7$ and a subthreshold swing of 0.7 V/dec. The OTFT on polyimide film has been detached from the glass support and laminated on a plastic support of $130\;{\mu}m-thick$ PET film. After the detach process, in spite of the degrading of its field-effect mobility, the OTFT showed high $I_{on}/I_{off}$ as high $as{\sim}10^6$.

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Unfolded Histidine-Tagged Protein is Immobilized to Nitrilotriacetic Acid-Nickel Beads, But Not the Nickel-Coated Glass Slide

  • Cho Min-Ho;Ahn Sun-Young;Park Heon-Yong
    • Genomics & Informatics
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    • v.4 no.3
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    • pp.133-136
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    • 2006
  • The adsorption of proteins on the surface of glass slides is essential for construction of protein chips. Previously, we prepared a nickel-coated plate by the spin-coating method for immobilization of His-tagged proteins. In order to know whether the structural factor is responsible for the immobilization of His-tagged proteins to the nickel-coated glass slide, we executed a series of experiments. First we purified a His-tagged protein after expressing the vector in E. coli BL21 (DE3). Then we obtained the unfolding curve for the His-tagged protein by using guanidine hydrochloride. Fractions unfolded were monitored by internal fluorescence spectroscopy. The ${\Delta}G_{H20}$ for unfolding was $2.27kcal/mol{/pm}0.52$. Then we tested if unfolded His-tagged proteins can be adsorbed to the nickel-coated plate, comparing with $Ni^{2+}-NTA$ (nitrilotriacetic acid) beads. Whereas unfolded His-tagged proteins were adsorbed to $Ni^{2+}-NTA$ beads, they did not bind to the nickel-coated plate. In conclusion, a structural factor is likely to be an important factor for constructing the protein chips, when His-tagged proteins will immobilize to the nickel-coated slides.

Al-doped ZnO via Sol-Gel Spin-coating as a Transparent Conducting Thin Film

  • Nam, Gil-Mo;Kwon, Myoung-Seok
    • Journal of Information Display
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    • v.10 no.1
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    • pp.24-27
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    • 2009
  • A simple nonalkoxide sol-gel route for depositing an Al-doped ZnO thin film on a glass substrate was derived in this study. The initial Al dopant concentration in the sol-gel preparation varied and ranged from 0 to 5%. The sol-gel-derived thin films showed c-plane preferred crystallization of their hexagonal phase, with nanosized grain structures. First and second post-heat-treatments were carried out to improve the film’s electrical resistivity. The carrier density and the Hall mobility were measured and discussed to explain the electrical resistivity. The optical transmittance within the visible range showed compatible properties, which indicates the possible use of A1-doped ZnO as a transparent electrode in flat panel displays.

The Substitution Effect of Boron on Reentrant Behavior of Rapidly Solidified FeMnZr Alloys

  • Moon, Y.M;Kim, K.S;Yu, S.C;Srinivas, V
    • Journal of Magnetics
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    • v.9 no.4
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    • pp.113-115
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    • 2004
  • The magnetization properties have been measured for amorphous $Fe_{82}Mn_{8-x}B_xZr_{10}$ (x = 0-8) alloys. The temperature dependence of magnetization for these alloys shows the existence of antiferromagnetic couplings between Fe atoms in low fields at low temperatures. The magnetic parameters, obtained from the magnetization behavior are consistent with the presence of mixed magnetic state. The Curie temperature and magnetic moment increased with an increase of the concentration of B and spin glass like transition observed at low temperature decreases and finally vanishes at x = 8 at %. Our result suggests that the substitution of B for Mn seems to cause an increase of magnetic order.

A Study on the low temperature magnetic properties of Fe-Cr-Ni alloys (Fe-Cr-Ni 합금의 저온에서의 자기적 성질에 관한 연구)

  • 안병덕;김진옥;장경호;송기영
    • Journal of the Korean Magnetics Society
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    • v.3 no.4
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    • pp.277-283
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    • 1993
  • The temperature dependence of DC magnetic susceptibilities of three austenitic Fe-Cr-Ni stainless alloys were measured in the temperature range of 4.2 and 300 K. Two alloys support a general magnetic description of austen-itic stsinless steels in terms of a two-magnetic-phase (spin glass + superparamagnetic cluster) model and one alloy shows magnetic double transition phenomena. Also this study shows that incressing the Ni/Cr ratio in Fe-Cr-Ni alloys causes a increase of the DC susceptibility peak value and a decrease of the magnetic transition temperature.

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Characteristics of ATO Thin Films Prepared by Sol-Gel Process (졸겔법으로 제조된 ATO 박막의 특성 연구)

  • 구창영;이동근;이희영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.192-195
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    • 2000
  • Antimony doped tin oxyde thin films have been deposited by sol-gel method using non-alkoxide precursor SnCl$_2$$.$2H$_2$O as host and SbC1$_3$ as dopant material. Using spin coating method, thin films of thickness up to 200nm have been uniformly deposited on Corning 1737F non-alkali glass substrates. Effect of Sb doping concentration and heat treatment on electrical and optical properties was investigated. Heat treatment was performed at the temperature from 350$^{\circ}C$ to 650$^{\circ}C$ in flowing O$_2$. The resulting ATO films showed widely changing electrical resistivity and optical transmittance values in the visible spectrum depending on the composition and firing condition.

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Fabrication and Characteristics of a Highly Sensitive GMR-SV Biosensor for Detecting of Micron Magnetic Beads (미크론 자성비드 검출용 바이오센서에 대한 고감도 GMR-SV 소자의 제작과 특성 연구)

  • Choi, Jong-Gu;Lee, Sang-Suk;Park, Young-Seok
    • Journal of the Korean Magnetics Society
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    • v.22 no.5
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    • pp.173-177
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    • 2012
  • The multilayer structure of glass/Ta(5.8 nm)/NiFe(5 nm)/Cu(t nm)/NiFe(3 nm)/FeMn(12 nm)/Ta(5.8 nm) as typical GMR-SV (giant magnetoresistance-spin valve) films is prepared by ion beam sputtering deposition (IBD). The coercivity and magnetoresiatance ratio are increased and decreased for the decrease of Cu thickness when the thickness of nonmagnetic Cu layer from is varied 2.2 nm to 3.0 nm. It means that the decrease of non-magntic layer is effected to the interlayer exchange coupling of pinned layer and the spin configuration array of free layer. For experiment of detecting and dropping of magnetic beads we used the GMR-SV sensor with glass/Ta/NiFe/Cu/NiFe/FeMn/Ta structure. From the comparison of before and after for the dropping status of magnetic bead, the variations of MR ratio, $H_{ex}$, and $H_c$ are showed 0.9 %, 3 Oe, and 2 Oe, respectively. The fabrication of GMR-SV sensor was included in the process of film deposition, photo-lithography, ion milling, and MR measurement. Further, GMR-SV device can be easily integrated so that detecting biosensor on a single chip becomes possible.

Magnetoresistance of Single-type and Dual-type GMR-SV Multilayer Thin Films with Top and Bottom IrMn Layer (상부와 하부 IrMn층을 갖는 단일구조 및 이중구조 거대자기저항-스핀밸브 다층박막의 자기적 특성 비교 분석)

  • Choi, Jong-Gu;Kim, Su-Hee;Choi, Sang-Heon;Lee, Sang-Suk
    • Journal of the Korean Magnetics Society
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    • v.27 no.4
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    • pp.115-122
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    • 2017
  • The antiferromagnet IrMn based four different GMR-SV multilayers on Corning glass were prepared by using ion beam deposition and DC magnetron sputtering system. The magnetoresistance (MR) properties for single-type and dual-type GMR-SV multilayer films were investigated through the measured major and minor MR curves. The exchange bias coupling field ($H_{ex}$) and coercivity ($H_c$) of pinned layer, the $H_c$ and interlayer exchange coupling field ($H_{int}$) of free layer for the dual-type structure GMR-SV multilayer films consisted of top IrMn layer were 410 Oe, 60 Oe, 1.6 Oe, and 7.0 Oe, respectively. The minor MR curve of two free layers was performed the squarelike feature having a MR ratio of 8.7 % as the sum of 3.7 % and 5.0 %. The value of average magnetic field sensitivity (MS) was maintained at 2.0 %/Oe. Also, the magnetoresistance properties of the single-type and dual-type structure GMR-SV multilayer films consisted of bottom IrMn layer were decreased more than those of top IrMn layer. Two antiparallel states of magnetization spin arrays of the pinned and free layers in the dual-type GMR-SV multilayer films occurred the maximum MR value by the effect of spin dependence scattering.

Magnetoresistive Properties of Array IrMn Spin Valves Devices (어레이 IrMn 스핀밸브 소자의 자기저항특성 연구)

  • Ahn, M.C.;Choi, S.D.;Joo, H.W.;Kim, G.W.;Hwang, D.G.;Rhee, J.R.;Lee, S.S.
    • Journal of the Korean Magnetics Society
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    • v.17 no.4
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    • pp.156-161
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    • 2007
  • To develop array magnetic sensors, specular-type giant magnetoresistive- spin valve (GMR-SV) film of Glass/Ta(5)MiFe(7)/IrMn(10)NiFe(5)/$O_2$/CoFe(5)/Cu(2.6)/CoFe(5)/$O_2$/NiFe(7)/Ta(5)(nm) was deposited by using a high-vacuum sputtering system. One of 15 way sensors in the area of $8{\times}8mm^2$ was Patterned a size of $20{\times}80{\mu}m^2$ in multilayer sample by Photo-lithography. All of 15 sensors with Cu electrodes were measured a uniform magnetic properties by 2-probe method. The highest magnetic sensitivity of MR and output voltage measured nearby an external magnetic field of 5 Oe were MS = 0.5%/Oe and ${\triangle}$V= 3.0 mV, respectively. An easy-axis of top-free layers of $CoFe/O_2/NiFe$ with shape anisotropy was perpendicular to one of bottom-pinned layers $IrMn/NiFe/O_2/CoFe$. When the sensing current increased from 1 mA to 10 mA, the output working voltage uniformly increased and the magnetic sensitivity was almost stable to use the nano-magnetic devices with good sensitive properties.

Post-annealing Effect of Giant Magnetoresistance-Spin Valve Device for Sensor (센서용 거대자기저항 스핀밸브소자의 열처리 효과)

  • Lee, Sang-Suk;Park, Sang-Hyun;Soh, Kwang-Sup;Joo, Ho-Wan;Kim, Gi-Wang;Hwang, D.G.
    • Journal of the Korean Magnetics Society
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    • v.17 no.4
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    • pp.172-177
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    • 2007
  • In order to detect of the magnetic property in the cell unit, we studied the GMR-SV (giant magnetoresistance-spin valves) biosensor, which was depended on the micro patterned features according to two easy directions of longitudinal and transversal axes. Here, the multi layer structure was glass/NiO/NiFe/CoFe/Cu/CoFe/NiFe. The uniaxial anisotropy direction was applied to the patterned biosensor during the deposition and vacuum post-annealing at $200^{\circ}C$ under the magnitude of 300 Oe, respectively. Considering the magnetic shape anisotropy effect, the size of micro patterned biosensor was a $2{\times}5{\mu}m^2$ after the photo lithography process. By our experimental results, we confirmed that the best condition of GMR-SV biosensor should be the same direction of the axis sensing current and the easy axis of pinned NiO/NiFe/CoFe triple layer oriented to the width direction of device, and the direction of the easy axis of free CoFe/NiFe bilayer was according to the longitudinal direction of device.