• Title/Summary/Keyword: 수직자기 이방성

Search Result 111, Processing Time 0.024 seconds

Exchange Bias Perpendicular Magnetic Anisotropy and Thermal Stability of (Pd/Co)N/FeMn Multilayer ((Pd/Co)N/FeMn 다층막에서의 교환바이어스 수직자기이방성과 열적안정성)

  • Joo, Ho-Wan;An, Jin-Hee;Kim, Bo-Keun;Kim, Sun-Wook;Lee, Kee-Am;Lee, Sang-Suk;Hwang, Do-Geun
    • Journal of the Korean Magnetics Society
    • /
    • v.14 no.4
    • /
    • pp.127-130
    • /
    • 2004
  • Magnetic properties and thermal stability by exchange biased perpendicular magnetic anisotropy in (Pd/Co)$_{N}$FeMn multilayer deposited by do magnetron sputtering system are investigated. We measured the perpendicular magnetization curves of (Pd(0.8nm)/Co(0.8nm)$_{5}$FeMn multilayer as function of FeMn thickness and annealing temperature. As FeMn thickness increases from 0 to 21nm, the perpendicular exchange bias(Hex) obtained 127 Oe at FeMn thickness 15nm. As the annealing temperature increases to 24$0^{\circ}C$, the E$_{ex}$ increased from 115 Oe to 190 Oe and disappeared exchange biased perpendicular magnetic anisotropy effect at 33$0^{\circ}C$.

제일원리 계산에 의한 Fe/Pt (001) 표면의 평형 구조 및 자기이방성 연구

  • Lee, Eung-Gwan;Choe, Hui-Chae;Hwang, Yu-Bin;Jeong, Yong-Jae
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2011.02a
    • /
    • pp.316-316
    • /
    • 2011
  • 제일원리 계산으로 Fe/Pt (001) 표면의 표면상태도를 계산하고 표면상태도로 부터 얻어진 평형 Fe/Pt (001) 표면구조의 자기이방성에너지를 계산하였음. 계산된 표면상태도로 부터 Fe-rich $L1_2$ 구조와 수직 $L1_0$ 구조가 가장 안정한 표면 Fe/Pt (001) 구조임이 밝혀졌음. 제일원리로 계산 된 두 구조의 자기이방성에너지를 관측하여 두 구조의 자기용이축이 모두 [001] 방향으로 정렬 됨을 확인하였다. 자기이방성에너지가 격자 변화와 표면 형성 중 어떤 원인에 의해 발생하는지 판단하기 위해서 표면구조, 벌크구조, 및 표면구조와 동일한 격자상수를 가진 벌크구조를 비교 하였다. 비교 결과에 의해 자기이방성에너지의 주 원인은 표면 형성임이 밝혀졌으며 이를 좀 더 명확히 하기위해 상태밀도함수를 계산하였다. 상태밀도함수 계산 결과 Fe 원자의 $3d_{z2}$ 오비탈의 페르미 준위 아래에서의 상태가 표면이 형성되면서 증가하는 것을 관측하였으며 이는 [001] 방향으로의 자기이방성을 증가시키는 오비탈이므로 표면 형성에 따른 자기이방성에너지 증가는 Fe 원자의 $3d_{z2}$ 오비탈에 의함이 판명되었다.

  • PDF

Magnetism and Magnetocrystalline Anisotropy of Ni/Fe(001) Surface: A First Principles Study (Ni/Fe(001)의 자성과 자기이방성에 대한 제일원리계산)

  • Kwon, Oryong;Hong, Soon Cheol
    • Journal of the Korean Magnetics Society
    • /
    • v.25 no.4
    • /
    • pp.101-105
    • /
    • 2015
  • Recent theoretical calculations predicted that a system composed exclusively of 3d transition metals without 4d/5d transition metals or rare earth metals can have strong perpendicular magnetocrystalline anisotropy (MCA) if Fe and Ni layers are arranged appropriately. They considered only Fe-terminated surfaces, noting that Fe/MgO(001) and CoFeB/MgO(001) show strong perpendicular MCA. In this paper, we investigate magnetism and MCA of Ni/Fe(001) surface where Ni layer is positioned at the surface, by using complementarily the first principles calculational methods of Vienna Ab-initio Simulation Package (VASP) and Full-potential Linearized Augmented Plane Wave (FLAPW) method. Comparing results of magnetism and MCA obtained by VASP with the results by FLAPW method, we find the VASP results do not show big difference from results by FLAPW method. Magnetic moments of Fe and Ni are enhanced due to strong hybridization between Fe and Ni bands. MCA of Ni/Fe(001) is parallel to the surface, which implies the surface termination plays a crucial role in determining MCA of a system.

Influence of Layer-thickness and Annealing on Magnetic Properties of CoSiB/Pd Multilayer with Perpendicular Magnetic Anisotropy (박막 두께 및 열처리가 수직자기이방성을 갖는 CoSiB/Pd 다층박막의 자기적 특성에 미치는 영향)

  • Jung, Sol;Yim, Haein
    • Journal of the Korean Magnetics Society
    • /
    • v.26 no.3
    • /
    • pp.76-80
    • /
    • 2016
  • CoSiB is the amorphous ferromagnetic material and multilayer consisting of CoSiB and Pd has perpendicular magnetic anisotropic property. PMA has strong advantages for STT-MRAM. Moreover, amorphous materials have two advantages more than crystalline materials: no grain boundary and good thermal stability. Therefore, we studied the magnetic properties of multilayers consisting of the $Co_{75}Si_{15}B_{10}$ with PMA. In this study, we investigated the magnetic property of the [CoSiB (3, 4, 5, and 6) ${\AA}$/Pd(11, 13, 15, 17, 19,and $24{\AA})]_5$ multilayers and found the annealing temperature dependence of the magnetic property. The annealing temperature range is from room temperature to $500^{\circ}C$. The coercivity and the saturation magnetization of the CoSiB/Pd multilayer system have a close association with the annealing temperature. Moreover, the coercivity especially shows a sudden increasing at the specific annealing temperature.