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Tryhuk V.V.,Brest State University | Ravinski A.F.,Brest State University | Ravinski A.F.,Bialystok Technical University | Makoed I.I.,Brest State University | And 2 more authors.
International Conference on Oxide Materials for Electronic Engineering, OMEE 2012 | Year: 2012

The Bi1-xGdxFeO3 (x = 0 - 0.2) ceramics were prepared by a solid-state reaction technique. Studies of magnetic and magnetoelectric properties were carried out. Due to the R3c → Pnma structural change, the spiral modulated spin structure collapses continuously with increasing Gd content and strongly enhances magnetization and magnetoelectric coefficient at x > 0.1. Studies of lattice dynamics of pure BiFeO3 were conducted ab-initio by means of density functional theory in order to shed light on ferroelectric instability. © 2012 IEEE. Source

Muzychenko D.A.,Moscow State University | Savinov S.V.,Moscow State University | Mantsevich V.N.,Moscow State University | Maslova N.S.,Moscow State University | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

By means of low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy we demonstrate the existence of spatial oscillations in the local electron density of states of clean Ge (111) 2×1 surfaces. The oscillations appear exclusively in the vicinity of boundaries between domains with different atomic arrangements and are present only within a limited range of tunneling voltages approximately between 0.2 and 0.8 V. From the spectroscopy measurements we are able to extract the energy versus wave-vector dispersion relation of the spatial oscillations in the local electron density of states. Relying on a tight-binding based model, we are able to link the observed phenomena to two-dimensional Tamm surface states that are formed within the semiconductor band gap and that are scattered at domain boundaries where translational symmetry is broken. © 2010 The American Physical Society. Source

Schouteden K.,Institute for Nanoscale Physics and Chemistry INPAC | Van Haesendonck C.,Institute for Nanoscale Physics and Chemistry INPAC
Journal of Physics Condensed Matter | Year: 2010

Deposition of Co atoms on Au(111) surfaces leads to the formation of self-organized bilayer Co nanowires at the step edges between adjacent narrow Au(111) terraces. Scanning tunneling microscopy and spectroscopy at low temperatures is used to probe the influence of the finite dimensions on the local density of states for both the Co wires and the narrow Au terraces. Confinement of Au surface state electrons to narrow Au terraces causes a shift of the Au surface state onset energy to higher energies. For the Co nanowires discrete energy levels are observed. Moreover, standing wave patterns occur at the surface of both the Au and the Co. The patterns increase in complexity with increasing energy. All Co nanowires formed at the edges of narrow Au terraces reveal a characteristic maximum in the local density of states at a significantly different energy when compared to the Co islands that are formed on large Au terraces. The experimental results can be interpreted in terms of a simple particle-in-a-box model. © 2010 IOP Publishing Ltd. Source

Schouteden K.,Institute for Nanoscale Physics and Chemistry INPAC | Volodin A.,Institute for Nanoscale Physics and Chemistry INPAC | Muzychenko D.A.,Moscow State University | Chowdhury M.P.,Institute for Nanoscale Physics and Chemistry INPAC | And 3 more authors.
Nanotechnology | Year: 2010

Discrete image-potential states (ISs) are revealed at double-walled carbon nanotubes by means of scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) in the distance-voltage z(V) spectroscopy mode. The nanotubes are supported by flat Au(111) substrates. Due to the high sensitivity of the hot IS electrons to local variations of the surface potential, they can be considered as a sensitive probe to investigate interactions with the supporting substrate and impurities or defects at the nanotube surface. ISs provide information on the local electronic structure as well as on the electron dynamics at supported nanotubes. © 2010 IOP Publishing Ltd. Source

Wu L.H.,Tsinghua University | Wu L.H.,Beijing National Center for Electronic Microscopy | Wu L.H.,Shanghai Aircraft Design and Research Institute | Zhang X.,Tsinghua University | And 6 more authors.
Applied Physics Letters | Year: 2011

Nonsaturating positive magnetoresistance (MR) of intrinsic bulk silicon (i-Si) was observed at forward bias, exhibiting an almost linear behavior at high magnetic fields (5 T Source

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