1 / 18

Asymmetric Mixing Behavior in Co-Al System: Theory and Experimental Study

This research paper explores the theoretical and experimental investigation of the asymmetric mixing behavior in the Co-Al system. It analyzes the atomic deposition behavior and thin film growth behavior of Co on Al and Al on Co, and examines the magnetic behavior of Co-Al compounds. The study provides valuable insights into the interfacial structure and chemical diffusion in nanoscale spintronic devices.

dgoto
Download Presentation

Asymmetric Mixing Behavior in Co-Al System: Theory and Experimental Study

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Co-Al 시스템의 비대칭적 혼합거동에 관한 이론 및 실험적 고찰 김상필1,2, 이승철1, 이광렬1, 정용재2 1. 한국과학기술연구원 미래기술연구본부 2. 한양대학교 세라믹공학과 박재영, 황정남 연세대학교 물리학과

  2. CMSEL Hanyang Univ. Introduction 1~2nm Typical structure of spintronic device Major Materials Issue is the interfacial structure and chemical diffusion in atomic scale

  3. CMSEL Hanyang Univ. Atomic deposition behavior Al on Co(0001) Co on Al(111) TOP VIEW Simulation Results

  4. CMSEL Hanyang Univ. Calculation Methods Adatom (normal incident  0.1 eV) 300K Initial Temperature 300K Constant Temperature Fixed Atom Position • Co-Al eam potential* • x,y-axis : Periodic Boundary Condition • z-axis : Open Surface • Deposition rate:1.306 × 10-1 nm/nsec • MD calc. step : 0.5fs * C. Vailhe et al. J. Mater. Res.,12 No. 10 2559 (1997). Simulation Results

  5. CMSEL Hanyang Univ. 3ML Al on Co(001) 3ML Co on Al(001) Thin Film Growth Behavior Atomic configurations Layer density No mixing & Sharp Interface Mixing & Interface alloying • Significantly different thin film growth behavior was reported Simulation Results

  6. CMSEL Hanyang Univ. Co Al (1) (2) (3) (4) Mixing Criteria Local Acceleration Activation Barrier for Mixing (1) 3.5eV (2) (3) (4) Reaction Coordinate Simulation Results

  7. CMSEL Hanyang Univ. (bond direction) a o a a a c1 c2 c2 Da a o o Da o a c1 A a intensity B d (angle) Ion Scattering Spectroscopy CoAxial Impact Collision Ion Scattering Spectroscopy (CAICISS) • Energy range of ~ keV → penetration depth : < 10 Å • It can analyzethe 3-dim. atomic structure of crystal surface and sub-surface by classical approximation of scattering Atomic geometry and shadow cone at various incident angles Variation of intensity of ions scattered by target atoms Experimental Evidences

  8. CMSEL Hanyang Univ. hcp site × × fcc site × × On top site Bridge site Polar [1100]; clean Co(0001) surface Experimental Evidences

  9. CMSEL Hanyang Univ. OnTop site(s) Bridge fcc hcp Al atom(s) 1.8 ± 0.05 Å Ah1’, Af1’ 1st Co layer Ah1,,Af1 Ah2’, Af2’ Ah2 2nd Co layer Polar scan curves  along [1100] direction DFT calculation results Experimental Evidences

  10. CMSEL Hanyang Univ. Atomic deposition behavior Al on Co(0001) Simulation Results

  11. CMSEL Hanyang Univ. Al(001) [100] 1st A11 2nd A121 A123 A122 3rd A132 A130 4.05 Å 4th 4.05 Å Polar [100]; clean Al(001) surface A121 (31.7°) A121 (58.3°) A132 (32.7°) A11 (12.9°) A122 (11.52°) A122 (26.4°) A132 (20.4°) A130 (79.1°) Experimental Evidences

  12. CMSEL Hanyang Univ. A11 Polar [100]: B2 structure [100] 1st Al 2nd Co 3rd A130 A131 C232 C230 C231 4.05 Å 4th 2.867 Å  B2-CoAl alloy was formed on Al(001) surface Experimental Evidences

  13. CMSEL Hanyang Univ. Spin-Up Spin-Down Magnetic Behavior of Co-Al system Stable intermetallic compound  B2(CsCl) structure B2 - CoAl Ab-initio calculations B2 - CoAl FCC - Al HCP - Co Nonmagnetic Metal Nonmagnetic Metal Magnetic Metal  The perfectly ordered B2-CoAl does not show any magnetic behavior Simulation Results

  14. CMSEL Hanyang Univ. MOKE (Magneto-Optic Kerr effects) Capping layer (50 A) Capping layer (50A) Capping layer (50 A) Co (30 A) Al (30 A) Co (30 A) Co (30 A) Cu buffer layer (1500 A) Al (840 A) Cu buffer layer (1500 A) Si substrate Si substrate Si substrate Experimental Measurement Experimental Evidences

  15. CMSEL Hanyang Univ. Asymmetric Alloy Effect Co Al Al Co Experimental Evidences

  16. CMSEL Hanyang Univ. Cap/Co/Buffer/Si(001) sample Experimental Evidences

  17. CMSEL Hanyang Univ. ~10 Å Thickness of Mixing Region Co: Ferromagnetic GMR structure CoAl: Nonmagnetic Co: Ferromagnetic Experimental Evidences

  18. CMSEL Hanyang Univ. Conclusions Magnetic Behavior of CoAl Deposition Behavior of Co on Al Deposition Behavior of Al on Co Experimental Evidences

More Related