Ing. Vojtěch Uhlíř, Ph.D.
E-mail:   uhlir@fme.vutbr.cz  WWW:   http://physics.fme.vutbr.cz Dept.:   Institute of Physical Engineering Position:   Assistant Professor

Publications:

• UHLÍŘ, V.; PIZZINI, S.; ROUGEMAILLE, N.; CROS, V.; JIMÉNEZ, E.; RANNO, L.; FRUCHART, O.; URBÁNEK, M.; GAUDIN, G.; CAMARERO, J.; TIEG, C.; SIROTTI, F.; WAGNER, E.; VOGEL, J.:
  Direct observation of Oersted-field-induced magnetization dynamics in magnetic nanostripes,
  PHYSICAL REVIEW B, Vol.83, (2011), No.2, pp.020406-1-020406-4, ISSN 1098-0121
  journal article - other
• UHLÍŘ, V.; PIZZINI, S.; ROUGEMAILLE, N.; NOVOTNÝ, J.; CROS, V.; JIMÉNEZ, E.; FAINI, G.; HEYNE, L.; SIROTTI, F.; TIEG, C.; BENDOUNAN, A.; MACCHEROZZI, F.; BELKHOU, R.; GROLLIER, J.; ANANE, A.; VOGEL, J.:
  Current-induced motion and pinning of domain walls in spin-valve nanowires studied by XMCD-PEEM,
  PHYSICAL REVIEW B, Vol.81, (2010), No.22, pp.224418-1-224418-10, ISSN 1098-0121
  journal article - other
• URBÁNEK, M.; UHLÍŘ, V.; BÁBOR, P.; KOLÍBALOVÁ, E.; HRNČÍŘ, T.; SPOUSTA, J.; ŠIKOLA, T.:
  Focused ion beam fabrication of spintronic nanostructures: an optimization of the milling process,
  NANOTECHNOLOGY, Vol.21, (2010), No.14, pp.145304-1-145304-7, ISSN 0957-4484
  journal article - other
• PIZZINI, S.; UHLÍŘ, V.; VOGEL, J.; ROUGEMAILLE, N.; LARIBI, S.; CROS, V.; JIMÉNEZ, E.; CAMARERO, J.; TIEG, C.; BONET, E.; BONFIM, M.; MATTANA, R.; DERANLOT, C.; PETROFF, F.; ULYSSE, C.; FAINI, G.; FERT, A.:
  High Domain Wall Velocity at Zero Magnetic Field Induced by Low Current Densities in Spin Valve Nanostripes,
  Applied Physics Express, Vol.2, (2009), No.2, pp.023003-1-023003-3, ISSN 1882-0778
  journal article - other
• MANCHON, A.; DUCRUET, C.; LOMBARD, L.; AUFFRET, S.; RODMACQ, B.; DIENY, B.; PIZZINI, S.; VOGEL, J.; UHLÍŘ, V.; HOCHSTRASSER, M.; PANACCIONE, G.:
  Analysis of oxygen induced anisotropy crossover in Pt/Co/MOx trilayers,
  Journal of Aplied Physics, Vol.104, (2008), No.4, pp.043914-1-043914-7, ISSN 0021-8979
  journal article - other
• PLŠEK, R.; UHLÍŘ, V.; URBÁNEK, M.; SPOUSTA, J.; ŠIKOLA, T.:
  Měření magnetických vlastností tenkých vrstev pomocí magnetooptického Kerrova jevu,
  Jemná mechanika a optika, Vol.52, (2008), No.6, pp.184-186, ISSN 0447-6441
  journal article - other
• MANCHON, A.; PIZZINI, S.; VOGEL, J.; UHLÍŘ, V.; LOMBARD, L.; DUCRUET, C.; AUFFRET, S.; RODMACQ, B.; DIENY, B.; HOCHSTRASSER, M.; PANACCIONE, G.:
  X-ray analysis of oxygen-induced perpendicular magnetic anisotropy in Pt/Co/AlOx trilayers,
  J. Magnetism Magn. Mat., Vol.320, (2008), No.13, pp.1889-1993, ISSN 0304-8853
  journal article - other
• MANCHON, A.; PIZZINI, S.; VOGEL, J.; UHLÍŘ, V.; LOMBARD, L.; DUCRUET, C.; AUFFRET, S.; RODMACQ, B.; DIENY, B.; HOCHSTRASSER, M.; PANACCIONE, G.:
  X-ray analysis of the magnetic influence of oxygen in Pt/Co/AlOx trilayers,
  Journal of Aplied Physics, Vol.103, (2008), No.7, pp.07A912-1-07A912-3, ISSN 0021-8979
  journal article - other

List of publications at Portal BUT

Abstracts of most important papers:

• UHLÍŘ, V.; PIZZINI, S.; ROUGEMAILLE, N.; CROS, V.; JIMÉNEZ, E.; RANNO, L.; FRUCHART, O.; URBÁNEK, M.; GAUDIN, G.; CAMARERO, J.; TIEG, C.; SIROTTI, F.; WAGNER, E.; VOGEL, J.:
  Direct observation of Oersted-field-induced magnetization dynamics in magnetic nanostripes,
  PHYSICAL REVIEW B, Vol.83, (2011), No.2, pp.020406-1-020406-4, ISSN 1098-0121
  journal article - other
  We have used time-resolved x-ray photoemission electron microscopy to investigate the magnetization dynamics induced by nanosecond current pulses in NiFe/Cu/Co nanostripes. A large tilt of the NiFe magnetization in the direction transverse to the stripe is observed during the pulses.We show that this effect cannot be quantitatively understood from the amplitude of the Oersted field and the shape anisotropy. High-frequency oscillations observed at the onset of the pulses are attributed to precessional motion of the NiFe magnetization about the effective field. We discuss the possible origins of the large magnetization tilt and the potential implications of the static and dynamic effects of the Oersted field on current-induced domain-wall motion in such stripes.
• UHLÍŘ, V.; PIZZINI, S.; ROUGEMAILLE, N.; NOVOTNÝ, J.; CROS, V.; JIMÉNEZ, E.; FAINI, G.; HEYNE, L.; SIROTTI, F.; TIEG, C.; BENDOUNAN, A.; MACCHEROZZI, F.; BELKHOU, R.; GROLLIER, J.; ANANE, A.; VOGEL, J.:
  Current-induced motion and pinning of domain walls in spin-valve nanowires studied by XMCD-PEEM,
  PHYSICAL REVIEW B, Vol.81, (2010), No.22, pp.224418-1-224418-10, ISSN 1098-0121
  journal article - other
  Very large average velocities, up to 600 m/s, have been found for domain-wall motion driven by 3-ns-long pulses of electric current in zero magnetic field in the NiFe layer of 200-nm-wide NiFe/Cu/Co nanowires. For longer pulses, the domain-wall motion is strongly hindered by pinning potentials. Dipolar interactions between the NiFe and Co layers caused by anisotropy inhomogeneities have been identified as the most important among the different potential sources of DW pinning. The domain-wall velocities increase with current density, but a substantial drop is observed at current densities above 4.1011 A/m2.
• URBÁNEK, M.; UHLÍŘ, V.; BÁBOR, P.; KOLÍBALOVÁ, E.; HRNČÍŘ, T.; SPOUSTA, J.; ŠIKOLA, T.:
  Focused ion beam fabrication of spintronic nanostructures: an optimization of the milling process,
  NANOTECHNOLOGY, Vol.21, (2010), No.14, pp.145304-1-145304-7, ISSN 0957-4484
  journal article - other
  Focused ion beam (FIB) milling has been used to fabricate magnetic nanostructures (wires, squares, discs) from single magnetic layers (Co, permalloy) and spin-valve (permalloy/Cu/Co) multilayers (thicknesses 5 - 50 nm) prepared by ion beam sputtering deposition. Milled surfaces of metallic thin films typically exhibit residual roughness, which is also transferred onto the edges of the milled patterns. This can lead to domain wall pinning and influence the magnetization behaviour of the nanostructures. We have investigated the milling process and the influence of the FIB parameters (incidence angle, dwell time, overlap and ion beam current) on the roughness of the milled surface. It has been found that the main reasons for increased roughness are different sputter yields for various crystallographic orientations of the grains in polycrystalline magnetic thin films. We have found that the oblique ion beam angle, long dwell time and overlap <1 are favourable parameters for suppression of this intrinsic roughness. Finally, we have shown how to determine the ion dose necessary to mill through the whole thin film up to the silicon substrate from scanning electron microscopy (SEM) images only.
• PIZZINI, S.; UHLÍŘ, V.; VOGEL, J.; ROUGEMAILLE, N.; LARIBI, S.; CROS, V.; JIMÉNEZ, E.; CAMARERO, J.; TIEG, C.; BONET, E.; BONFIM, M.; MATTANA, R.; DERANLOT, C.; PETROFF, F.; ULYSSE, C.; FAINI, G.; FERT, A.:
  High Domain Wall Velocity at Zero Magnetic Field Induced by Low Current Densities in Spin Valve Nanostripes,
  Applied Physics Express, Vol.2, (2009), No.2, pp.023003-1-023003-3, ISSN 1882-0778
  journal article - other
  Current-induced magnetic domain wall motion at zero magnetic field is observed in the permalloy layer of a spin-valve-based nanostripe using photoemission electron microscopy. The domain wall movement is hampered by pinning sites, but in between them high domain wall velocities (exceeding 150 m/s) are obtained for current densities well below 10^12 A/m2, suggesting that these trilayer systems are promising for applications in domain wall devices in case of well controlled pinning positions. Vertical spin currents in these structures provide a potential explanation for the increase in domain wall velocity at low current densities.
• MANCHON, A.; DUCRUET, C.; LOMBARD, L.; AUFFRET, S.; RODMACQ, B.; DIENY, B.; PIZZINI, S.; VOGEL, J.; UHLÍŘ, V.; HOCHSTRASSER, M.; PANACCIONE, G.:
  Analysis of oxygen induced anisotropy crossover in Pt/Co/MOx trilayers,
  Journal of Aplied Physics, Vol.104, (2008), No.4, pp.043914-1-043914-7, ISSN 0021-8979
  journal article - other
  Extraordinary Hall effect and x-ray spectroscopy measurements have been performed on a series of Pt/Co/MOx trilayers (M=Al, Mg, Ta, etc.) in order to investigate the role of oxidation in the onset of perpendicular magnetic anisotropy at the Co/MOx interface. It is observed that varying the plasma oxidation time modifies the magnetic properties of the Co layer, inducing a magnetic anisotropy crossover from in plane to out of plane. We focused on the influence of plasma oxidation on Pt/Co/AlOx perpendicular magnetic anisotropy. The interfacial electronic structure is analyzed via x-ray photoelectron spectroscopy measurements. It is shown that the maximum of out-of-plane magnetic anisotropy corresponds to the appearance of a significant density of Co-O bondings at the Co/AlOx interface. (C) 2008 American Institute of Physics.