13 research outputs found

    Oxide films in spintronics

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    A wealth of information in one accessible book. Written by international experts from multidisciplinary fields, this in-depth exploration of oxide ultrafhin films covers all aspects of these systems, starting with preparation and characterization, and going on to geometrical and electronic strucutre, as well as applications in current and future systems an device

    Electric field control of magnetic anisotropies and magnetic coercivity in Fe/BaTiO3 (001) heterostructures

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    Electric field control of magnetic anisotropies and magnetic coercivity in Fe/BaTiO3 (001) heterostructure

    Bandstructure line-up of epitaxial Fe/MgO/Ge heterostructures: A combined x-ray photoemission spectroscopy and transport study

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    The bandstructure line-up of Fe/MgO/Ge heterostructures with various Ge doping has been determined by x-ray photoemission spectroscopy. The MgO layer causes a sizable depinning of the Fermi level in Ge for light n-1015 cm−3 and moderate p-doping 1018 cm−3, but not for heavy n-doping 1020 cm−3. The Fermi level instead stays essentially in the middle of the MgO gap for all the investigated doping. This picture agrees with transport measurements only for moderate n- or p-doping, while we demonstrate that for heavy n-doping the analysis of the conductance versus temperature fails in predicting the Schottky barrier height

    Epitaxial growth of Fe/MgO/Ge(001) heterostructures

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    We report on the growth of epitaxial Fe/MgO heterostructures on Ge(0 0 1) by Molecular Beam Epitaxy. The better crystal quality and interfacial chemical sharpness at the oxide–semiconductor interface have been obtained by growing MgO at room temperature, followed by a post-annealing at 773 K, on top of a p(2 1)-Ge(0 0 1) clean surface. The growth of Fe at room temperature followed by annealing at 473 K gives the best epitaxial structure with optimized crystallinity of each layer compatible with limited chemical interdiffusion. Tunneling devices based on the epitaxial Fe/MgO/Ge heterostructure have been micro-fabricated and tested in order to probe the electrical properties of the MgO barrier. The current–voltage characteristics clearly show that tunneling is the dominant phenomenon, thus indicating that this system is very promising for practical applications in electronics and spintronics

    Epitaxial growth of Fe/BaTiO3 heterostructures

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    Epitaxial growth of Fe/BaTiO3 heterostructure

    Dispositivo rilevatore ottico spintronico

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    Dispositivo rilevatore ottico spintronic

    Observation of anomalous acoustic phonon dispersion in SrTiO3 by broadband stimulated Brillouin scattering

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    Observation of anomalous acoustic phonon dispersion in SrTiO3 by broadband stimulated Brillouin scatterin

    Sharp Fe/MgO/Ge(001) epitaxial heterostructures for tunneling junctions

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    We report on the growth of epitaxial Fe/MgO/Ge(001) heterostructures by molecular beam epitaxy. The lowest oxidation and highest sharpness of the MgO/Ge interface, corresponding to a transition layer on the order of one Ge unit cell, is obtained for room temperature growth of the MgO layer followed by annealing in a vacuum at 500 C. In these conditions, the MgO layer grows epitaxially on Ge(001) with the [110] direction parallel to the [100] direction of Ge, at variance with the cube-on-cube growth on Si(001) and GaAs(001). However, in some cases, the cube-on-cube growth mode of MgO on Ge competes with the mode involving a 45 rotation, as revealed by transmission electron microscopy and photoelectron diffraction data on MgO films grown at 300 C without postannealing, and on p-doped Ge substrates. For the Fe overlayer, in all the cases reported, room temperature growth followed by annealing up to 200 C gives rise to a sharp interface and the well-known 45 rotation of the Fe lattice with respect to the MgO lattice

    Aberration corrected scanning transmission electron microscopy and electro energy loss spectroscopy studies of epitaxial Fe/MgO/(001)Ge heterostructures

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    Aberration correction in the scanning transmission electron microscope combined with electron energy loss spectroscopy allows simultaneous mapping of the structure, the chemistry and even the electronic properties of materials in one single experiment with spatial resolutions of the order of one A ° ngstro¨m. Here the authors will apply these techniques to the characterization of epitaxial Fe/MgO/(001)Ge and interfaces with possible applications for tunneling junctions, and the authors will show that epitaxial MgO films can be grown on a (001)Ge substrates by molecular beam epitaxy and how it is possible to map the chemistry of interfaces with atomic resolution
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