Ing. Martin Zelený, Ph.D.
E-mail:   zeleny@fme.vutbr.cz  Pracoviště:   Ústav materiálových věd a inženýrství odbor strukturní a fázové analýzy Zařazení:   Vedoucí odboru Místnost:   A3/404 Pracoviště:   Ústav materiálových věd a inženýrství odbor strukturní a fázové analýzy Zařazení:   Odborný asistent Místnost:   A3/404

Aktuálně garantované předměty:

• Fyzika materiálů (5FM)
• Fyzika materiálů (5FM-A)
• Modelování materiálů I (WMO)
• Modelování materiálů I (WMO-A)
• Úvod do fyziky materiálů (WUF)

Vybrané publikace:

• ZELENÝ, M.; FRIÁK, M.; ŠOB, M.:
  Ab initio study of energetics and magnetism of Fe, Co, and Ni along the trigonal deformation path,
  PHYSICAL REVIEW B, Vol.83, (2011), No.18, pp.184424-184430, ISSN 1098-0121
  článek v časopise - ostatní, Jost
• ZELENÝ, M.; NATTER, F. D.; BIEDERMANN, A.; HAFNER, J.:
  Ultrathin Mn layers on Rh(001): Investigations using scanning tunneling microscopy and density functional calculations,
  PHYSICAL REVIEW B, Vol.82, (2010), No.16, pp.165422-165436, ISSN 1098-0121
  článek v časopise - ostatní, Jost
• ZELENÝ, M.; ŠOB, M.; HAFNER, J.:
  Noncollinear magnetism in manganese nanostructures,
  PHYSICAL REVIEW B, Vol.80, (2009), No.14, pp.144414-144432, ISSN 1098-0121
  článek v časopise - ostatní, Jost
• ZELENÝ, M.; ŠOB, M.; HAFNER, J.:
  Ab initio density functional calculations of ferromagnetism in low-dimensional nanostructures: From nanowires to nanorods,
  PHYSICAL REVIEW B, Vol.79, (2009), No.13, pp.134421-134430, ISSN 1098-0121
  článek v časopise - ostatní, Jost

Seznam publikací na portálu VUT

Anotace nejvýznamnějších prací:

• ZELENÝ, M.; FRIÁK, M.; ŠOB, M.:
  Ab initio study of energetics and magnetism of Fe, Co, and Ni along the trigonal deformation path,
  PHYSICAL REVIEW B, Vol.83, (2011), No.18, pp.184424-184430, ISSN 1098-0121
  článek v časopise - ostatní, Jost
  A detailed theoretical study of structural and magnetic behavior of iron, cobalt, and nickel along the trigonal transformation paths at various volumes per atom is presented. The total energies are calculated by a spin-polarized full-potential linearized augmented plane wave method within the generalized gradient approximation and are displayed in contour plots as functions of trigonal c/a ratio and volume per atom. The borderlines between various magnetic modification are shown for Fe and Ni. In the case of Ni, these phase boundaries between nonmagnetic and ferromagnetic phases occur even at the experimental value of volume per atom. On the other hand, Co keeps its ferromagnetic order in the whole region of the volume and shape deformation studied. Fe does not exhibit any transition between the ferromagnetic and nonmagnetic arrangement, but at low volumes per atom around the fcc structure, phase boundaries between the ferromagnetic high-spin, ferromagnetic low-spin, and antiferromagnetic states have been found. Fe and Co exhibit minima on the curve of the energy difference between ferromagnetic (FM) and nonmagnetic states in the same areas where Ni loses its FM ordering. Both structures do not exhibit any higher symmetry, but there is a coalescence of the second and third and fifth and sixth coordination spheres (c/a = 1.27) or of the third and fourth coordination spheres (c/a = 2.83).
• ZELENÝ, M.; ŠOB, M.; HAFNER, J.:
  Noncollinear magnetism in manganese nanostructures,
  PHYSICAL REVIEW B, Vol.80, (2009), No.14, pp.144414-144432, ISSN 1098-0121
  článek v časopise - ostatní, Jost
  We present ab initio spin-density-functional calculations of the magnetic properties of Mn nanostructures with a geometry varying between a straight linear wire and a three-dimensional nanorod, including collinear and noncollinear, commensurate and incommensurate magnetic configurations. With decreasing tension along the axis of the nanostructure we find a series of transitions first from a straight to a zigzag wire, then to planar triangular or hexagonal stripes and further to a nanorod consisting of a periodic stacking of distorted octahedra. At local equilibrium all nanostructures are in a high-moment state, with absolute values of the local magnetic moments per atom varying between 3.79 mu_B for a straight noncollinear antiferromagnetic Mn monowire, 3.54 mu_B for a triangular collinear antiferromagnetic stripe, 3.40 mu_B for a hexagonal collinear ferrimagnetic stripe, and 2.96 mu_B for an octahedral noncollinear ferrimagnetic nanorod. For all low-dimensional nanostructures except the monowire we find collinear and noncollinear magnetic structures to be energetically nearly degenerate, if the geometric and magnetic degrees of freedom are relaxed simultaneously. The energetic consequences of a modest change in the interatomic distances are comparable to those of a large canting of the magnetic moments. Compression of the nanostructures leads to a decrease in the magnetic moments.
• ZELENÝ, M.; LEGUT, D.; ŠOB, M.:
  Ab initio study of Co and Ni under uniaxial and biaxial loading and in epitaxial overlayers,
  PHYSICAL REVIEW B, Vol.78, (2008), No.22, pp.224105-224115, ISSN 1098-0121
  článek v časopise - ostatní, Jost
  A detailed theoretical study of structural and magnetic behaviors of cubic cobalt and nickel along the bcc-fcc Bain transformation paths as well as of hcp cobalt and nickel loaded uniaxially along the [0001] direction at various atomic volumes is presented. The total energies are calculated by spin-polarized full-potential linearized augmented plane-wave method within the generalized gradient approximation and are displayed in contour plots as functions of tetragonal or hcp c/a ratio and atomic volume; the borderlines between the ferromagnetic and nonmagnetic phases are shown. Stability of possible ferromagnetic phases of bcc nickel is analyzed. The calculated contour plots are used to explain and predict the lattice parameters and magnetic states of tetragonal and hcp cobalt and nickel overlayers on various (001) or (111) substrates, respectively. In case of tetragonally deformed structures, the stresses needed to keep the thin films coherent with the substrates are also determined and all Co and Ni overlayers on (001) cubic substrates are predicted to be ferromagnetic. The agreement of available experimental data for Co and Ni overlayers with the results of bulk calculations is remarkable and suggests that the geometrical effect of the substrate, i.e., imposing the lattice dimensions of the substrate in the plane of the film to the film material, is one of the most important factors determining the structure and properties of the film. In this way, the lattice parameters of Co and Ni overlayers may be very well understood in terms of properties of appropriately deformed bulk Co and Ni.
• ZELENÝ, M.; ŠOB, M.:
  Theoretical studies of epitaxially grown Co and Ni thin films on (111) metallic substrates,
  PHYSICAL REVIEW B, Vol.77, (2008), No.15, pp.155435-155440, ISSN 1098-0121
  článek v časopise - ostatní, Jost
  Total energies of hcp and trigonally distorted fcc Co and Ni are studied from first principles. Regions of stability of these structures are found and the behavior of the total energies is used to explain and predict the lattice parameters and magnetic states of Co and Ni thin films on various (111) substrates. The stresses needed to keep the thin films coherent with the substrates are also determined. The theoretical results agree surprisingly well with available experimental data.