• 제목/요약/키워드: Ag(001) surface

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Magnetic properties of ferromagnetic-antiferromagnetic bi-layers with different spin configuration

  • 김원동;박주상;황찬용;;;박명규;김재영
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.304-304
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    • 2011
  • We investigated the effect of different spin direction of anti-ferromagnetic layer on the magnetic properties of ferromagnetic layer in Fe-NiO and Fe-CoO bi-layer systems. For Fe-NiO system, we prepared the clean MgO(001) surface half-covered with 20 nm Ag films as a substrate for magnetic layers. Then we grew NiO wedge layers on the substrate, and added 8 monolayer(ML) Fe layers on the wedge layer. We examined magnetic properties of the bi-layer system using the surface magnetic optical Kerr effect(SMOKE) and X-ray magnetic linear dichroism(XMLD). From SMOKE measurement we observed the coercivity enhancement due to the set-up of anti-ferromagnetic order of NiO films in both of the Fe/NiO/MgO(001) and Fe/NiO/Ag/MgO(001) system. The most remarkable results in our observation is that the coercivity enhancement of Fe/NiO/Ag/MgO(001) is much larger than that of Fe/NiO/MgO(001). XMLD experiments confirmed the out-of-plane spin direction of NiO layers in Fe/NiO/MgO(001) and in-plane spin-direction of NiO layers in Fe/NiO/Ag/MgO(001), and we concluded that the origin of large enhancement of coercivity is due to the strong parallel coupling between Fe layers and NiO layers. We also confirmed that this strong parallel coupling maintained across the thin Ag layer inserted between Fe and NiO layers. For Fe-CoO system, we prepared Fe/CoO/Ag(001) and Fe/CoO/MnO(001) systems and observed much larger coercivity enhancement in Fe/CoO/Ag(001).

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면심입방 금속(Cu, Rh, Pd, Ag) (001) 표면 위의 철 단층의 자성 (Magnetism of Fe Monolayers on Nonmagnetic fcc Transition Metal (Cu, Rh, Pd, and Ag) (001) Surfaces)

  • 윤원석;차기범;노태환;한동호;홍순철
    • 한국자기학회지
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    • 제19권5호
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    • pp.165-170
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    • 2009
  • 준안정 상태인 덩치 fcc Fe는 반강자성 상태가 기저 상태인 것으로 알려져 있고 적절한 fcc 금속 표면 위에 fcc Fe를 성장시킬 수 있음이 보고된 바 있다. 본 연구에서는 fcc 금속 (001) 표면 위의 Fe 원자층의 자성을 연구하기 위해 Cu(001), Rh(001), Pd(001), Ag(001) 표면 위의 Fe 단층의 자성을 제일원리계산 방법 중 자성 연구에 가장 적합한 총퍼텐셜선형보강평면파(fullpotential linearized augmented plane wave; FLAPW) 방법을 사용하여 연구하였다. 고려한 계 중에서 2차원 격자상수가 가장 작은 Cu(001) 표면과 가장 큰 Ag(001) 표면 위의 Fe 단층은 강자성이 비교적 큰 에너지 차이로 Fe-fcc 금속 층간 거리에 관계없이 안정적이었고, 중간 크기의 2차원 격자상수를 가진 Rh(001)과 Pd(001) 표면 위의 Fe 단층은 반강자성 상태가 안정적이었으나, 층간 거리가 커짐에 따라 강자성 상태가 안정적일 수도 있는 것으로 계산되었다. 계산된 자기모멘트는 1Fe/Cu(001), 1Fe/Rh(001), 1Fe/Pd(001), 1Fe/Ag(001)의 강자성 상태에서 2.811, 2.945, 2.987, 2.990 $_{{\mu}B}$이었고, 반강자성 상태에서는 2.624, 2.879, 2.922, 3.001 $_{{\mu}B}$이었다.

Ag(001) 표면 위에 놓인 Fe 선의 자성과 전자구조 (First-principles Study on Magnetism and Electronic Structure of Fe Chain on Ag(001))

  • 김영구;이재일
    • 한국자기학회지
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    • 제15권4호
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    • pp.217-220
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    • 2005
  • 제일원리적 에너지 띠 계산 방법인 전 전자 총 퍼텐셜 선형보강평면파동(all-electron full-potential linearized augmented plane ave) 방법에 일반기울기근사(generalized gradient approximation)를 채용하여 Ag(001) 표면 위에 [110] 방향으로 놓인 Fe 선의 전자구조와 자성을 이론적으로 연구하였다. Fe 선의 원자당 자기모멘트는 $3.02\;{\mu}_B$로 Cu(001) 위에 놓인 Fe[110] 선의 값($2.99\;{\mu}_B$) 보다 약간 컸다. Fe 선의 자기모멘트가 상당히 증가한 것은 이웃한 결합수가 줄어들고 그 결과로 Fe-d 전자상태의 띠폭이 줄어들어 국소화 되고 스핀분리가 증가하였기 때문이다. Fe-d 전자상태의 띠 폭은 약 1.6eV였으며 스핀분리는 약 3.2 eV였다.

Evolution of Cube Texture in the Nickel-Silver-Stainless steel Multi-layer Sheet

  • Lee, Hee-Gyoun;Jung, Yang-Hong;Hong, Gye-Won
    • Progress in Superconductivity
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    • 제1권1호
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    • pp.51-55
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    • 1999
  • A Ni/Ag/Stainless steel 310S(SS310S) multi-layer sheet has been fabricated by a combination of vacuum brazing, cold rolling and texture annealing processes. After heat-treating the thin Ni/Ag/SS310S multi-layer sheet at $900^{\circ}C$ for 2h, development of (100)<001>cube texture on Ni surface was revealed by (111) pole figure. Quantitative chemical analysis was made by EPMA for the cross-section of the Ni/Ag/SS310S multi-layer sheet. EPMA results showed that Ag diffusion into the Ni layer, which may suppress the cube texture development, was negligible. A small amount of Cr atoms were detected in the Ni layer. It showed that Ag can be used as a chemical barrier of alloying element atoms in Ni layer for the Ni/Ag/SS310S multi-layer sheet and a strong cube texture was developed for the Ni layer in the Ni/Ag/SS310S multi-layer sheet.

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A Study on the Trend of Changes in the Positive Rate of Hepatitis B Surface Antigens and Antibodies over the Last 9 Years in One Health Care Center

  • Kang-Sil Lee;Sang-Ha Kim;Young-Bin Yu;Young-Kwon Kim
    • 대한의생명과학회지
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    • 제29권4호
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    • pp.314-320
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    • 2023
  • The purpose of this study was to provide basic data on hepatitis B infection control in the community through the results of the hepatitis B surface antigen and antibody tests conducted at the Cheongyang-County Health Medical Center. From 2012 to 2020, we retrospectively analyzed the HBsAg, HBsAb, HBeAg, HBeAb, and HBV DNA results of 7,329 hepatitis B-related testers. Among 7,329 subjects, the HBsAg positivity rate was 1.7%, and the positivity rate according to age was the highest at 4.4% in their 30s, 4.2% in their 40s, 4.1% in their 50s, 2.0% in their 60s, 1.9% in their 70s and over, and 10 it was shown in the order of 0.3% from less than large. The HBsAb positivity rate was 43.1% for men, 38.2% for men, and 46.7% for women (P<0.001). To summarize the above results, for infection control of hepatitis B in Cheongyang-County, hepatitis surface antigen proton management is required for those in their 30s or older, and it is thought that efforts to acquire immunity are necessary for those in their 20s or younger.