• Title/Summary/Keyword: Overlayer

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Magnetic Properties and Relaxation of Vanadium Monolayer on Pd(001) Surface

  • Landge, Kalpana K.;Bialek, Beata;Lee, Jae-Il
    • Journal of Magnetics
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    • v.15 no.2
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    • pp.45-50
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    • 2010
  • We investigated the magnetism of vanadium monolayers on a Pd(001) surface. The electronic structure and the magnetic properties of the V/Pd(001) system were determined with the use of the full-potential linearized augmented plane-wave method within the general gradient approximation. Three magnetic configurations were studied: non-, ferro-, and antiferromagnetic. From the total energy calculations, we found that the V/Pd(001) system is the most stable in the antiferromagnetic configuration. The importance of relaxation on the magnetic properties of the systems was also studied. It was found that the Pd(001) surface covered with a V monolayer undergoes considerable relaxation in which the spacing between Pd layers increases in all three magnetic configurations. Contrary to the Pd interlayer spacing, the distance between the V overlayer and the topmost Pd layer is reduced. The interlayer spacing between the V overlayer and the Pd surface layer is the largest for the antiferromagnetic configuration. In the relaxed antiferromagnetic structure, the magnitude of the calculated magnetic moments on the V atoms was $1.31\;{\mu}_B$. The presence of the vanadium monolayer does not affect the paramagnetic properties of the Pd(001) surface.

Epitaxial Growth of Ge on Si(100) and Si(111) Surfaces (Si(100)와 Si(111) 표면의 Ge 에피 성장 연구)

  • Khang, Yun-Ho;Kuk, Young
    • Journal of the Korean Vacuum Society
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    • v.2 no.2
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    • pp.161-165
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    • 1993
  • The geometrical and electronic structure of epitaxially grown Ge on Si(100) and Si(111) surfaces has been studied by scanning tunneling microscopy. Since Ge atoms could be distinguished from Si atoms by scanning tunneling spectroscopy and voltage dependent STM images, the growth mode of the added layer could be studied. On the (100) surface with a (2${\times}$1) reconstruction, Ge overlayer grow preferentially on the B type step edges at 720K. On the (111) surface, Ge overlayer also grow on the step edges with (7${\times}$7) and (5${\times}$5) structure depending on their coverage and annealing temperature.

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ZnO/Cu/Al2O3 transparent heaters fabricated by magnetron sputtering (마그네트론 스퍼터링법으로 제조된 ZnO/Cu/Al2O3 투명 면상 발열체 연구)

  • Min, Changheum;Choi, Dooho
    • Journal of the Korean institute of surface engineering
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    • v.55 no.5
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    • pp.284-291
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    • 2022
  • Herein, we studied ultrathin Cu-layer-based transparent heaters embedded between a ZnO underlayer and an Al2O3 overlayer. The anti-reflecting functions for the ZnO and Al2O3 layers by independently varying the layer thicknesses, with the Cu layer thickness fixed at 8.5 nm. The smallest visible light transmittance of 11.1% was achieved when the overlayer and underlayer thicknesses were 90 and 30 nm, respectively. We conducted electrically driven Joule heating test for the Cu layers having thicknesses of 8.5 nm (Rs: 14.7 Ohm/sq.) and 19 nm (Rs: 3.4 Ohm/sq.). External voltages were increased with an interval of 2 V until irreversible failures occurred at temperatures of ~390 ℃ and 550 ℃, respectively. At each voltage increase before heater failures, the heater exhibited superior thermal response with the heater temperatures reaching over 90% of the final temperatures. The heaters also showed excellent reproducibility when turning on and off the heater repeatedly.

Study on Effect of Various Underlayer on Bilayer Agglomerlation (다양한 하지층이 이중층의 응집현상에 미치는 영향에 관한 연구)

  • Ha, J.H.;Ryu, D.H.;Im, H.W.;Jung, J.M.;Choi, H.J.;Hong, I.G.;Koh, J.H.;Koo, S.M.;Kamiko, M.;Ha, J.G.
    • Journal of the Korean Vacuum Society
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    • v.21 no.5
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    • pp.233-241
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    • 2012
  • We have deposited the bilayer consisted of the underlayer and the overlayer by using DC magnetron sputter on Single crystal MgO (001) substrate. This bilayer was fabricated at fixed annealing temperature and time. We have controlled agglomeration effect by changing of the bilayer thickness. Finally, we have made the self-organization and nano-structured film. In this processing, we have made nano-dot which consists of the underlayer and the overlayer, unlike the existing method called the agglomeration effect in the single layer. The underlayer has deposited using Ti, Cr and Co. And the overlayer has deposited with Ag. Through the analysis of Atomic force microscopy (AFM), the microstructure of underlayer is observed by AFM to confirm the formation of nano-dot. As the nano-dot through above processing, we have found that the nano-dot has the different shape. As a result, when we manufactured nano-dot through the agglomeration effect of bi-layer, the best matching material is Ti for underlayer. And also, we have found that MgO/Ti/Ag samples have been grown expitaxially toward the direction of MgO (001) by X-ray Diffraction analysis.

Magnetic Properties of Transition Metal Monolayers on Ta(001) Surfaces

  • Youn, S.J.;Hong, S.C.
    • Journal of Magnetics
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    • v.13 no.4
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    • pp.140-143
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    • 2008
  • The magnetic and structural properties of transition metal (Mn, Fe, Co) monolayers on Ta(001) surfaces are investigated theoretically by using the first principles full-potential linearized augmented plane wave method. Mn and Fe monolayers become ferromagnetic on Ta(001) surfaces while Co monolayers becomes non-magnetic. The paramagnetism of Co monolayers is explained by the Stoner theory of magnetism. The magnetic coupling of a transition metal overlayer with a substrate is ascribed to the orbital hybridization between the s and d orbitals of the transition metal.

ELECTRONIC STRUCTURE AND MAGNETISM OF V/W(001) (V/W(001) 계의 전자 구조와 자성)

  • 장영록;김인기;이재일
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.36-37
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    • 2002
  • 귀금속(noble metal)이나 전이금속(transition metal) 밑층(substrate) 위에 높여진 금속 웃층(metal overlayer)의 자성(magnetism) 연구는 오랫동안 많은 관심의 대상이 되었고, 특히 전이금속을 웃층으로 사용한 경우에 대해서 많은 연구가 있었다 [1]. 전이금속 중에서 바나듐(vanadium; V)은 덩치(bulk) 상태에서는 자성을 가지지 않지만, 귀금속인 Ag(001) 혹은Cu(001) 위에 놓여지면 자성을 가지게 된다는 보고가 있었다 [2]. (중략)

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