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An external strain is suggested as an effective means to finely control the magnetic properties of a candidate medium for future spintronics devices. To demonstrate the potential of this concept, the biaxial strain effects on the magnetic moment of Co adatom on pyridinic N-doped graphene (PNG) sheet were investigated using density functional theory calculations. Under the strain from -5% to 5%, the magnetic moment of the Co adatom on PNG was increased continuously from 1.72 to 1.95 μ B . Also, Co adatoms are expected to be dispersed on the PNG surface without metal clustering in this range of applied strain due to its strong binding with the pyridinic nitrogen defects. From these results, it is anticipated that reliable control of magnetism in Co decorated PNG system is available by use of an external strain.

In this presentation, the magnetic properties and electronic structure of Cr incorporated SiC(100) surface, including the surface formation energy and the surface electronic structure, was extensively investigated using ab initio calculations. the surfaces of p(2times1) and c(4times2)-AUDD were employed to simulate the Si-terminated SiC(100) surface, and the c(2times2) was prepared to calculate the C-terminated surface. The total magnetic moment and the magnetization energy were obtained by the spin-polarized calculation for one Cr atom in the SiC(100) surface supercell. Due to the surface effect of SiC(100), the total magnetic moment of SiC(100):Cr-p(2times1) was found to be increased. The origin of the surface magnetism will be discussed in terms of the density of states and the wave function characteristics around the Fermi level.

Surface diffusion behaviors for Fe and Co adatoms on the MgO (001) surface were investigated using first-principles calculations. The potential energy calculations revealed that Fe and Co adatoms favored the on O site as initial adsorption site. The adsorption energies were calculated to be 1.97 and 0.73 eV for Fe and Co, respectively. Surface diffusion after the adsorption on O site was occurred by passing through the bridge site on the surface and energy barrier for the process was 0.54 eV for both adatoms. The magnetic moment of Co atoms on O site was 3.15 muB and the value was significantly reduced at the bridge site as 2.99 muB, while the corresponding value in vacuum state was 3.50 muB. Interestingly, the magnetic moment for Co adatom at the bridge site was increased by 0.08 muB compared to the case of adsorbed Co on O site. Spin polarization values for adatoms at the adsorption sites on the substrate were ranged from 82.9% to 100%

The morphology of Al thin-film growth on an Ni(001) substrate according to the variation incident energy of adatoms was investigated by molecular dynamics simulation. Al atoms apparently favored the layer-by-layer growth mode at a low incident angle. The growth mode of Al film was, however, changed to follow the island growth mode according to the increasing adatom incident angle. Interestingly, the steering effect due to atomic attraction, which results in rougher surface, was significantly observed. The steering effect was quantitatively investigated through the extensive measurement of the trajectory with the variation of incident energy and incident angle near the artificially structured Al step positioned on the Ni surface

The magnetic property of B2-Co/sub x/Al/sub 1-x/ as a function of Co atomic concentration was investigated using the ab initio method. The antistructured (AS) supercell model based on B2 structure was employed to calculate the magnetic moment of the Co/sub x/Al/sub 1-x/ compounds originated from spontaneous intermixing of Co atoms with Al surface atoms. In the case of Al-rich Co/sub x/Al/sub 1-x/, no apparent ferromagnetism was represented. However, the magnetic moment was calculated to be rapidly increased with Co concentration in the range above 50 atomic % and was saturated at a level of a pure HCP Co system. Ferromagnetism in Co/sub x/Al/sub 1-x/ alloys can be attributed to the existence of local BCC-Co and local AS-Co atoms.

Using molecular dynamics simulation, the morphology of Ni thin film growth on Ni(111) substrate according to the incident energy of adatoms was investigated. Ni atoms apparently favored the island growth mode at low incident energy. The growth mode of Ni film was, however, changed to follow layer-by-layer growth mode for the incident energy of 6 eV. The steering effect due to atomic attraction, which results in rougher surface, was significantly observed at low incident energy. The local acceleration for the corresponding steering effect was quantitatively calculated.