|
| |
|
| |
|
| |
|
|
Studium struktury a magnetismu FeCo při vysokých deformacích z prvních principů
Čák, Miroslav ; Legut, Dominik ; Šob, Mojmír
Total energies and magnetic moments of FeCo along the tetragonal deformation path are calculated using first-principles electronic structure methods. Total energies are displayed in a contour plot as a function of tetragonal distortion and volume; borderline between the ferromagnetic and nonmagnetic states is shown. The calculated energies may be used to predict the lattice parameters of FeCo thin films on various (001) substrates; here we study the FeCo film on the MgO(001) substrate. The calculated results are compared with available experimental data. The loss of magnetism of FeCo at low atomic volumes and large shape deformations is observed.
|
|
|
Možné transformační dráhy spojující struktury C11b, C40 and C54 v MoSi2
Káňa, Tomáš ; Legut, Dominik ; Šob, Mojmír
We suggest three transformation paths between the ideal C11b , C40 and C54 structures of transition-metal disilicides. These three structures can be regarded as different stackings of identical planes of atoms. Each suggested transformation path consists in shifting these atomic planes in three directions. The shift of planes is described by one parameter p <0;1>. Along each path, we calculate the total energy of MoSi2 as a function of p. Our results confirm the structural order C11b → C40 →C54 in MoSi2. The C11b–C54 path exhibits the largest energy barrier, 2.5 eV/f.u (f.u. means the formula unit). The energy barrier of the C11b–C40 path is lower, 1.7 eV/f.u. and finally the energy barrier of the C40–C54 path is the lowest one, 1.4 eV/f.u.
|
guest ::
