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2013


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Vision meets Robotics: The KITTI Dataset

Geiger, A., Lenz, P., Stiller, C., Urtasun, R.

International Journal of Robotics Research, 32(11):1231 - 1237 , Sage Publishing, September 2013 (article)

Abstract
We present a novel dataset captured from a VW station wagon for use in mobile robotics and autonomous driving research. In total, we recorded 6 hours of traffic scenarios at 10-100 Hz using a variety of sensor modalities such as high-resolution color and grayscale stereo cameras, a Velodyne 3D laser scanner and a high-precision GPS/IMU inertial navigation system. The scenarios are diverse, capturing real-world traffic situations and range from freeways over rural areas to inner-city scenes with many static and dynamic objects. Our data is calibrated, synchronized and timestamped, and we provide the rectified and raw image sequences. Our dataset also contains object labels in the form of 3D tracklets and we provide online benchmarks for stereo, optical flow, object detection and other tasks. This paper describes our recording platform, the data format and the utilities that we provide.

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pdf DOI [BibTex]

2013


pdf DOI [BibTex]


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Hybrid nanocolloids with programmed three-dimensional shape and material composition

Mark, A. G., Gibbs, J. G., Lee, T., Fischer, P.

NATURE MATERIALS, 12(9):802-807, 2013, Max Planck Press Release. (article)

Abstract
Tuning the optical(1,2), electromagnetic(3,4) and mechanical properties of a material requires simultaneous control over its composition and shape(5). This is particularly challenging for complex structures at the nanoscale because surface-energy minimization generally causes small structures to be highly symmetric(5). Here we combine low-temperature shadow deposition with nanoscale patterning to realize nanocolloids with anisotropic three-dimensional shapes, feature sizes down to 20 nm and a wide choice of materials. We demonstrate the versatility of the fabrication scheme by growing three-dimensional hybrid nanostructures that contain several functional materials with the lowest possible symmetry, and by fabricating hundreds of billions of plasmonic nanohelices, which we use as chiral metafluids with record circular dichroism and tunable chiroptical properties.

Max Planck Press Release.

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Video - Fabrication of Designer Nanostructures DOI [BibTex]


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Magnetoelastic coupling in epitaxial cobalt ferrite/barium titanate heterostructures

Gräfe, J., Welke, M., Bern, F., Ziese, M., Denecke, R.

Journal of Magnetism and Magnetic Materials, 339, pages: 84-88, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Chiral Colloidal Molecules And Observation of The Propeller Effect

Schamel, D., Pfeifer, M., Gibbs, J. G., Miksch, B., Mark, A. G., Fischer, P.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135(33):12353-12359, 2013 (article)

Abstract
Chiral molecules play an important role in biological and chemical processes, but physical effects due to their symmetry-breaking are generally weak. Several physical chiral separation schemes which could potentially be useful, including the propeller effect, have therefore not yet been demonstrated at the molecular scale. However, it has been proposed that complex nonspherical colloidal particles could act as ``colloidal molecules{''} in mesoscopic model systems to permit the visualization of molecular phenomena that are otherwise difficult to observe. Unfortunately, it is difficult to synthesize such colloids because surface minimization generally favors the growth of symmetric particles. Here we demonstrate the production of large numbers of complex colloids with glancing angle physical vapor deposition. We use chiral colloids to demonstrate the Baranova and Zel'dovich (Baranova, N. B.; Zel'dovich, B. Y. Chem. Phys. Lett. 1978, 57, 435) propeller effect: the separation of a racemic mixture by application of a rotating field that couples to the dipole moment of the enantiomers and screw propels them in opposite directions. The handedness of the colloidal suspensions is monitored with circular differential light scattering. An exact solution for the colloid's propulsion is derived, and comparisons between the colloidal system and the corresponding effect at the molecular scale are made.

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Video - Nanospropellers DOI [BibTex]

Video - Nanospropellers DOI [BibTex]


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Indirect absorption spectroscopy using quantum cascade lasers: mid-infrared refractometry and photothermal spectroscopy

Pfeifer, M., Ruf, A., Fischer, P.

OPTICS EXPRESS, 21(22):25643-25654, 2013 (article)

Abstract
We record vibrational spectra with two indirect schemes that depend on the real part of the index of refraction: mid-infrared refractometry and photothermal spectroscopy. In the former, a quantum cascade laser (QCL) spot is imaged to determine the angles of total internal reflection, which yields the absorption line via a beam profile analysis. In the photothermal measurements, a tunable QCL excites vibrational resonances of a molecular monolayer, which heats the surrounding medium and changes its refractive index. This is observed with a probe laser in the visible. Sub-monolayer sensitivities are demonstrated. (C) 2013 Optical Society of America

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DOI [BibTex]


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Plasmonic nanohelix metamaterials with tailorable giant circular dichroism

Gibbs, J. G., Mark, A. G., Eslami, S., Fischer, P.

APPLIED PHYSICS LETTERS, 103(21), 2013, Featured cover article. (article)

Abstract
Plasmonic nanohelix arrays are shown to interact with electromagnetic fields in ways not typically seen with ordinary matter. Chiral metamaterials (CMMs) with feature sizes small with respect to the wavelength of visible light are a promising route to experimentally achieve such phenomena as negative refraction without the need for simultaneously negative e and mu. Here we not only show that giant circular dichroism in the visible is achievable with hexagonally arranged plasmonic nanohelix arrays, but that we can precisely tune the optical activity via morphology and lattice spacing. The discrete dipole approximation is implemented to support experimental data. (C) 2013 AIP Publishing LLC.

Featured cover article.

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DOI [BibTex]

DOI [BibTex]


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Quantum cryo-sieving for hydrogen isotope separation in microporous frameworks: an experimental study on the correlation between effective quantum sieving and pore size

Oh, H., Park, K. S., Kalidindi, S. B., Fischer, R. A., Hirscher, M.

{Journal of Materials Chemistry A}, 1, pages: 3244-3248, Royal Society of Chemistry, Cambridge, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Gold nanocrystals in high-temperature superconducting films: creation of pinning patterns of choice

Katzer, C., Stahl, C., Michalowski, P., Treiber, S., Schmidl, F., Seidel, P., Albrecht, J., Schütz, G.

{New Journal of Physics}, 15(11), Institute of Physics Pub., Bristol, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Theory of scattering of crystal electrons at magnons

Haag, Michael, Illg, C., Fähnle, M.

{Physical Review B}, Published by the American Physical Society through the American Institute of Physics, Woodbury, NYAmerican Institute of Physics, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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The effect of magnetocrystalline anisotropy on the domain structure of patterned Fe2CrSi Heusler alloy thin films

Miyawaki, T., Foerster, M., Finizio, S., Vaz, C. A. F., Mawass, M.-A., Inagaki, K., Fukatani, N., Le Guyader, L., Nolting, F., Ueda, K., Asano, H., Kläui, M.

{Journal of Applied Physcis}, 114(7), American Institute of Physics, New York, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Ion beam lithography for Fresnel zone plates in X-ray microscopy

Keskinbora, K., Grévent, C., Bechtel, M., Weigand, M., Goering, E., Nadzeyka, A., Lloyd, P., Rehbein, S., Schneider, G., Follath, R., Vila-Comamala, J., Yan, H., Schütz, G.

{Optics Express}, 21(10):11747-11756, Optical Society of America, Washington, DC, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Is the angular momentum of a ferromagnetic sample after exposure to a fs laser pulse conserved?

Fähnle, M., Haag, M., Illg, C.

{Journal of Magnetism and Magnetic Materials}, 347, pages: 45-46, North-Holland, Amsterdam, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Grain boundaries as the controlling factor for the ferromagnetic behaviour of Co-doped ZnO

Straumal, B. B., Mazilkin, A. A., Protasova, S. G., Straumal, P. B., Myatiev, A. A., Schütz, G., Goering, E. J., Tietze, T., Baretzky, B.

{Philosophical Magazine}, 93(10-12):1371-1383, 2013 (article)

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DOI [BibTex]


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Magnetic properties of electrochemically prepared crystalline films of Prussian blue-based molecular magnets Kj CrIIk [CrIII(CN)6] l \mbox⋅ mH2O

Bhatt, P., Yusuf, S. M., Bhatt, R., Schütz, G.

{Journal of Solid State Electrochemistry}, 17, pages: 1285-1293, Springer-Verlag Germany, 2013 (article)

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DOI [BibTex]


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H2/D2 adsorption and desorption studies on carbon molecular sieves with different pore structures

Krkljus, I., Steriotis, T., Charalambopoulou, G., Gotzias, A., Hirscher, M.

{Carbon}, 57, pages: 239-247, Elsevier Science, Amsterdam [u.a.], 2013 (article)

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DOI [BibTex]


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X-ray magnetic circular dichroism strongly influenced by non-magnetic cover layers

Zafar, K., Audehm, P., Schütz, G., Goering, E., Pathak, M., Chetry, K. B., LeClair, P. R., Gupta, A.

{Journal of Electron Spectroscopy and Related Phenomena}, 191, pages: 1-6, Elsevier, Amsterdam, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Exchange bias in La0.7Sr0.3MnO3 / SrMnO3 / La0.7Sr0.3MnO3 trilayers

Jungbauer, M., Hühn, S., Michelmann, M., Goering, E., Moshnyaga, V.

{Journal of Applied Physcis}, 113(17), American Institute of Physics, New York, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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General decoupling procedure for expectation values of four-operator products in electron-phonon quantum kinetics

Teeny, N., Fähnle, M.

{Journal of Physics A: Mathematical and Theoretical}, 46(38), IOP Pub., London, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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SPD-induced changes of structure and magnetic properties in the Cu-Co alloys

Straumal, B. B., Protasova, S. G., Mazilkin, A. A., Kogtenkova, O. A., Kurmanaeva, L., Baretzky, B., Schütz, G., Korneva, A., Zieba, P.

{Materials Letters}, 98, pages: 217-221, Elsevier, Amsterdam, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Ferromagnetic behaviour of Fe-doped ZnO nanograined films

Straumal, B. B., Protasova, S. G., Mazilkin, A. A., Tietze, T., Goering, E., Schütz, G., Straumal, P. B., Baretzky, B.

{Beilstein Journal of Nanotechnology}, 4, pages: 361-369, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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The effect of magnetic anisotropy on the spin configurations of patterned La0.7Sr0.3MnO3 elements

Wohlhüter, P., Rhensius, J., Vaz, C. A. F., Heidler, J., Körner, H. S., Bisig, A., Foerster, M., Méchin, L., Gaucher, F., Locatelli, A., Niño, M. A., El Moussaoui, S., Nolting, F., Goering, E., Heyderman, L. J., Kläui, M.

{Journal of Physics: Condensed Matter}, 25, IOP Pub., Bristol, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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The avalanche process in gold covered MgB2 films

Stahl, C., Treiber, S., Schütz, G., Albrecht, J.

{Superconductor Science and Technology}, 26, IOP Pub., Bristol, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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MFU-4 - A metal-organic framework for highly effective H2/D2 separation

Teufel, J., Oh, H., Hirscher, M., Wahiduzzaman, M., Zhechkov, L., Kuc, A., Heine, T., Denysenko, D., Volkmer, D.

{Advanced Materials}, 25(4):635-639, Wiley-VCH Verlag, Weinheim, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Delayed magnetic vortex core reversal

Kammerer, M., Sproll, M., Stoll, H., Noske, M., Weigand, M., Illg, C., Fähnle, M., Schütz, G.

{Applied Physics Letters}, 102, American Institute of Physics, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Self-organized state formation in magnonic vortex crystals

Adolff, C. F., Hänze, M., Vogel, A., Weigand, M., Martens, M., Meier, G.

{Physical Review B}, 88(22), American Physical Society, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Erratum: Generalized Gilbert equation including inertial damping: Derivation from an extended breathing Fermi surface model [Phys. Rev. B 84, 172403 (2011)]

Fähnle, M., Steiauf, D., Illg, C.

{Physical Review B}, 88, American Physical Society, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Strain and composition dependence of orbital polarization in nickel oxide superlattices

Wu, M., Benckiser, E., Haverkort, M. W., Franco, A., Lu, J., Nwankwo, U., Brück, S., Audehm, P., Goering, E., Macke, S., Hinkov, V., Wochner, P., Christiani, G., Heinze, S., Logvenov, G., Habermeier, H., Keimer, B.

{Physical Review B}, 88, Published by the American Physical Society through the American Institute of Physics, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Efficient focusing of 8 keV X-rays with multilayer Fresnel zone plates fabricated by atomic layer deposition and focused ion beam milling

Mayer, M., Keskinbora, K., Grévent, C., Szeghalmi, A., Knez, M., Weigand, M., Snigirev, A., Snigereva, I., Schütz, G.

{Journal of Synchrotron Radiation}, 20, pages: 433-440, Published for the International Union of Crystallography by Munksgaard, Copenhagen, Denmark, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Rapid prototyping of Fresnel zone plates via direct Ga+ ion beam lithography for high-resolution x-ray imaging

Keskinbora, K., Grévent, C., Eigenthaler, U., Weigand, M., Schütz, G.

{ACS Nano}, 7(11):9788-9797, American Chemical Society, Washington, DC, 2013 (article)

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DOI [BibTex]


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Eine kryoflexible kovalente organische Gerüststruktur für die effiziente Trennung von Wasserstoffisotopien durch Quantensieben

Oh, H., Kalidindi, S. B., Um, Y., Bureekaew, S., Schmid, R., Fischer, R. A., Hirscher, M.

{Angewandte Chemie}, 125(50):13461-13464, Wiley-VCH Verl., Weinheim, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Ultrafast demagnetization after laser irradiation in transition metals: Ab initio calculations of the spin-flip electron-phonon scattering with reduced exchange splitting

Illg, C., Haag, M., Fähnle, M.

{Physical Review B}, 88, American Physical Society, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Phase diagram for magnetic vortex core switching studied by ferromagnetic absorption spectroscopy and time-resolved transmission x-ray microscopy

Martens, M., Kamionka, T., Weigand, M., Stoll, H., Tyliszczak, T., Meier, G.

{Physical Review B}, 87, Published by the American Physical Society through the American Institute of Physics, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Switching modes in easy and hard axis magnetic reversal in a self-assembled antidot array

Haering, F., Wiedwald, U., Nothelfer, S., Koslowski, B., Ziemann, P., Lechner, L., Wallucks, A., Lebecki, K., Nowak, U., Gräfe, J., Goering, E., Schütz, G.

{Nanotechnology}, 24, IOP Pub., Bristol, UK, 2013 (article)

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DOI Project Page [BibTex]

DOI Project Page [BibTex]


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Time-resolved imaging of nonlinear magnetic domain-wall dynamics in ferromagnetic nanowires

Stein, F.-U., Bocklage, L., Weigand, M., Meier, G.

{Scientific Reports}, 3, Nature Publishing Group, London, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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A cryogenically flexible covalent organic framework for efficient hydrogen isotrope separation by quantum sieving

Oh, H., Kalidindi, S. B., Um, Y., Bureekaew, S., Schmid, R., Fischer, R. A., Hirscher, M.

{Angewandte Chemie International Edition in English}, 52(50):13219-13222, Wiley-VCH Verlag GmbH & Co. KGaA, D-69451 Weinheim, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Unexpected room-temperature ferromagnetism in bulk ZnO

Chen, Y., Goering, E., Jeurgens, L., Wang, Z., Phillipp, F., Baier, J., Tietze, T., Schütz, G.

{Applied Physics Letters}, (103), American Institute of Physics, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Large-area hard magnetic L10-FePt and composite L10-FePt based nanopatterns

Goll, D., Bublat, T.

{Physica Status Solidi A-Applications and Materials Science}, 210(7):1261-1271, Wiley-VCH, Weinheim, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Wave modes of collective vortex gyration in dipolar-coupled-dot-array magnonic crystals

Han, D., Vogel, A., Jung, H., Lee, K., Weigand, M., Stoll, H., Schütz, G., Fischer, P., Meier, G., Kim, S.

{Scientific Reports}, 3, Nature Publishing Group, London, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Ferromagnetism of zinc oxide nanograined films

Straumal, B. B., Protasova, S. G., Mazilkin, A. A., Schütz, G., Goering, E., Baretzky, B., Straumal, P. B.

{Journal of Experimental and Theoretical Physics Letters}, 97(6):367-377, Pleiades Publishing, Inc., 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Hydrogen adsorption properties of platinum decorated hierarchically structured templated carbons

Oh, H., Gennett, T., Atanassov, P., Kurttepeli, M., Bals, S., Hurst, K. E., Hirscher, M.

{Microporous and Mesoporous Materials}, pages: 66-74, Elsevier, Amsterdam, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Extended s-d models for the dynamics of noncollinear magnetization: Short review of two different approaches

Fähnle, M., Zhang, S.

{Journal of Magnetism and Magnetic Materials}, 326, pages: 232-234, NH, Elsevier, Amsterdam, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Correlation between spin structure oscillations and domain wall velocities

Bisig, A., Stärk, M., Mawass, M., Moutafis, C., Rhensius, J., Heidler, J., Büttner, F., Noske, M., Weigand, M., Eisebitt, S., Tyliszczak, T., Van Wayenberge, B., Stoll, H., Schütz, G., Kläui, M.

{Nature Communications}, 4, Nature Publishing Group, London, 2013 (article)

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DOI [BibTex]


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Recent advances in use of atomic layer deposition and focused ion beams for fabrication of Fresnel zone plates for hard x-rays

Keskinbora, K., Robisch, A., Mayer, M., Grévent, C., Szeghalmi, A. V., Knez, M., Weigand, M., Snigireva, I., Snigirev, A., Salditt, T., Schütz, G.

{Proceedings of SPIE (The International Society for Optical Engineering)}, 8851, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Magnetic states in low-pinning high-anisotropy material nanostructures suitable for dynamic imaging

Büttner, F., Moutafis, C., Bisig, A., Wohlhüter, P., Günther, C. M., Mohanty, J., Geilhufe, J., Schneider, M., v. Korff Schmising, C., Schaffert, S., Pfau, B., Hantschmann, M., Riemeier, M., Emmel, M., Finizio, S., Jakob, G., Weigand, M., Rhensius, J., Franken, J. H., Lavrijsen, R., Swagten, H. J. M., Stoll, H., Eisebitt, S., Kläui, M.

{Physical Review B}, 87, Published by the American Physical Society through the American Institute of Physics, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Experimental and theoretical study of D2/H2 quantum sieving in a carbon molecular sieve

Gotzias, A., Charalambopoulou, G., Ampoumogli, A., Krkljus, I., Hirscher, M., Steriotis, T.

{Adsorption}, 19(2-4):373-379, Springer Science+Business Media, New York, 2013 (article)

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DOI [BibTex]

DOI [BibTex]

2006


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Chiral molecules split light: Reflection and refraction in a chiral liquid

Ghosh, A., Fischer, P.

PHYSICAL REVIEW LETTERS, 97(17), 2006, Featured highlight ‘Fundamental optical physics: Refraction’ Nature Photonics, Nov. 2006. (article)

Abstract
A light beam changes direction as it enters a liquid at an angle from another medium, such as air. Should the liquid contain molecules that lack mirror symmetry, then it has been predicted by Fresnel that the light beam will not only change direction, but will actually split into two separate beams with a small difference in the respective angles of refraction. Here we report the observation of this phenomenon. We also demonstrate that the angle of reflection does not equal the angle of incidence in a chiral medium. Unlike conventional optical rotation, which depends on the path-length through the sample, the reported reflection and refraction phenomena arise within a few wavelengths at the interface and thereby suggest a new approach to polarimetry that can be used in microfluidic volumes.

Featured highlight ‘Fundamental optical physics: Refraction’ Nature Photonics, Nov. 2006.

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DOI [BibTex]

2006


DOI [BibTex]


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Direct chiral discrimination in NMR spectroscopy

Buckingham, A., Fischer, P.

CHEMICAL PHYSICS, 324(1):111-116, 2006 (article)

Abstract
Conventional nuclear magnetic resonance spectroscopy is unable to distinguish between the two mirror-image forms (enantiomers) of a chiral molecule. This is because the NMR spectrum is determined by the chemical shifts and spin-spin coupling constants which - in the absence of a chiral solvent - are identical for the two enantiomers. We discuss how chirality may nevertheless be directly detected in liquid-state NMR spectroscopy: In a chiral molecule, the rotating nuclear magnetic moment induces an electric dipole moment in the direction perpendicular to itself and to the permanent magnetic field of the spectrometer. We present computations of the precessing electric polarization following a pi/2 pulse. Our estimates indicate that the electric polarization should be detectable in favourable cases. We also predict that application of an electrostatic field induces a chirally sensitive magnetization oscillating in the direction of the permanent magnetic field. We show that the electric-field-perturbed chemical shift tensor, the nuclear magnetic shielding polarizability, underlies these chiral NMR effects. (c) 2005 Elsevier B.V. All rights reserved.

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DOI [BibTex]

DOI [BibTex]


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NONLINEAR OPTICAL PROPERTIES OF CHIRAL LIQUIDS Electric-dipolar pseudoscalars in nonlinear optics

Fischer, P., Champagne, B.

In NON-LINEAR OPTICAL PROPERTIES OF MATTER: FROM MOLECULES TO CONDENSED PHASES, 1, pages: 359-381, Challenges and Advances in Computational Chemistry and Physics, 2006 (incollection)

Abstract
We give all overview of linear and nonlinear optical processes that can be specific to chiral molecules in isotropic media. Specifically, we discuss the pseudoscalars that underlie nonlinear optical activity and chiral frequency conversion processes in fluids. We show that nonlinear optical techniques open entirely new ways of exploring chirality: Sum-frequency-generation (SFG) at second-order and BioCARS at fourth-order arise in the electric-dipole approximation and do not require circularly polarized light to detect chiral molecules in solution. Here the frequency conversion in itself is a measure of chirality. This is in contrast to natural optical activity phenomena which are based on the interference of radiation from induced oscillating electric and magnetic dipoles, and which are observed as a differential response to right and left circularly polarized light. We give examples from our SFG experiments in optically active solutions and show how the application of an additional static electric field to sum-frequency generation allows the absolute configuration of the chiral solute to be determined via all electric-dipolar process. Results from ab initio calculations of the SFG pseudoscalar are presented for a number of chiral molecules

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[BibTex]

[BibTex]


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Ring-resonator-based frequency-domain optical activity measurements of a chiral liquid

Vollmer, F., Fischer, P.

OPTICS LETTERS, 31(4):453-455, 2006 (article)

Abstract
Chiral liquids rotate the plane of polarization of linearly polarized light and are therefore optically active. Here we show that optical rotation can be observed in the frequency domain. A chiral liquid introduced in a fiber-loop ring resonator that supports left and right circularly polarized modes gives rise to relative frequency shifts that are a direct measure of the liquid's circular birefringence and hence of its optical activity. The effect is in principle not diminished if the circumference of the ring is reduced. The technique is similarly applicable to refractive index and linear birefringence measurements. (c) 2006 Optical Society of America.

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DOI [BibTex]


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Sign of the refractive index in a gain medium with negative permittivity and permeability

Chen, Y., Fischer, P., Wise, F.

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 23(1):45-50, 2006 (article)

Abstract
We show how the sign of the refractive index in any medium may be derived using a rigorous analysis based on Einstein causality. In particular, we consider left-handed materials, i.e., media that have negative permittivities and permeabilities at the frequency of interest. We find that the consideration of gain in such media can give rise to a positive refractive index. (c) 2006 Optical Society of America.

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DOI [BibTex]

DOI [BibTex]