• Journal of Korean Vacuum Science & Technology
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• v.3 no.2
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• pp.134-138
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• 1999

We have setup a compact and useful in-situ SMOKE system in order to study surface magnetism of ultra-thin films. Since the longitudinal or polar magnetic fields can be applied to the sample by just rotating the sample manipulator, It is very simple to take hysteresis curve for in-plane or polar surface magnetism. The SMOKE system was tested by investigating the surface magnetism of ultra-thin Co film deposited on Pt(111) surface.

• Journal of Magnetics
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• v.13 no.4
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• pp.144-148
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• 2008

The size and surface effects on the magnetism of a fcc Fe (001) surface was investigated by performing firstprinciples calculations on 3, 5, 7, and 9 monolayers fcc Fe (001) single slabs with two different two-dimensional lattice constants, ${\alpha}=3.44{\AA}$ (System I) and 3.65 ${\AA}$ (System II), using the all-electron full-potential linearized augmented plane wave method within a generalized gradient approximation. The surface layers were coupled ferromagnetically to the subsurface layer in both systems. However, the magnetism of the inner layers was quite different from each other. While all the inner layers of System II were ferromagnetically coupled in the same way as the surface layer, the inner layers of System I showed a peculiar magnetism, bilayer antiferromagnetism. The calculated spin magnetic moments per Fe atom were approximately 2.7 and 2.9 ${\mu}_B$ at the surface for Systems I and II, respectively, due to the almost occupied Fe d-state being in the majority spin state and band narrowing. The spin orientations of System I were out-of-plane regardless of its thickness, whereas the orientation of System II changed from out-of-plane to in-plane with increasing thickness.

• Journal of Magnetics
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• v.1 no.1
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• pp.9-13
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• 1996

The effects of surface relaxation on surface and interface magnetism in Fe/Cr (001) are investigated using the highly precise all-electron total-energy full-potential linearized augmented plane wave method. The Fe-Cr interlayer spacing is deter-mined by total-energy calculation and it is found to be relaxed downward by 18%. For the relaxed system, the magnetic moment of surface Fe is highly suppressed to be $1.72\mu_B$compared to the unrelaxed case ($2.39\mu_B$). This reduction of magnetic moment is considered as a result of the enhanced hybridization between Fe-d and Cr-d states, which can be seen from the calculated density of states. This work suggests the importance of effect of relaxation to the surface and interface magnetism in Fe/Cr system.

• Journal of Magnetics
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• v.20 no.1
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• pp.1-7
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• 2015

We investigated the half-metallicity and magnetism at the (001) and (110) surfaces of YC in zinc-blende structure by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. From the calculated local density of states, we found that neither (001) nor (110) surface preserves the half-metallicity. While the magnetic moment of Y atom in the YC bulk is $0.116{\mu}_B$, it is $0.057{\mu}_B$ at the topmost layer of Y-terminated (001) surface. On the contrary, C-terminated (001) YC surface exhibits stronger magnetism than the bulk structure; the calculated magnetic moment on topmost C atom is $1.084{\mu}_B$, while that of C atom in the bulk structure is $0.423{\mu}_B$. The magnetic properties of the non-polar (110) YC surface are slightly enhanced as compared with the bulk structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.211-211
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• 2012

Using spin-polarized density-functional theory calculations, we find that the existence of either Peierls instability or antiferromagnetic spin ordering is sensitive to hydrogen passivation near the step. As hydrogens are covered on the terrace, the dangling bond electrons are localized at the step, leading to step-induced states. We investigate the competition between charge and spin orderings in dangling-bond (DB) wires of increasing lengths fabricated on an H-terminated vicinal Si(001) surface. We find antiferromagnetic (AF) ordering to be energetically much more favorable than charge ordering. The energy preference of AF ordering shrinks in an oscillatory way as the wire length increases. This oscillatory behavior can be interpreted in terms of quantum size effects as the DB electrons fill discrete quantum levels.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.55.1-55.1
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• 2008

• Journal of the Korean Magnetics Society
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• v.25 no.5
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• pp.139-143
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• 2015

The surface magnetism of the CsCl structured Co binary compounds, CoX (X = Ti, V, Nb) (001) surface was studied with the calculated electronic structure data obtained by the full-potential linearized augmented plane-wave (FLAPW) method. The magnetic moment of the surface Co atom of the Co-terminated CoTi(001) system was $1.19{\mu}_B$, which is enhanced compared with that of the Co atom in the center layer. The magnetic moment of the surface V atom in the V terminated the CoV(001) system was $1.64{\mu}_B$, which is more than twice of the center layered V atom. The magnetic moment of surface Co atom in the Co terminated CoV(001) system has the value of $1.34{\mu}_B$, little bit smaller than the bulk value. The magnetism was disappeared in the Co terminated CoNb(001) system, and the magnetic moment of the surface Nb atom in the Nb terminated CoNb(001) system was $0.26{\mu}_B$ which is little bit decreased compared to the center layer value.

• Journal of Magnetics
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• v.10 no.1
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• pp.1-4
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• 2005

We investigated the electronic structures and the magnetic properties of Ti-based intermetallic system of CoTi/FeTi/CoTi(110) surface and interface by using the all-electron full potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA). The calculated magnetic moments of interface Co and Fe atoms are 0.65 and 0.15 μ/sub B/, respectively. Surface and interface magnetism of CoTi/FeTi/CoTi(110) are discussed using the calculated density of states (DOS) and the spin densities.

• 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.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.101-105
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• 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.