# User submitted records

 2018-04-2016:00 [IMPULSE-2018-00205] Dissertation / PhD Thesis Winter, R. Strukturbestimmung ausgewählter Protein- und Lipidsysteme mit nicht-typischem Aggregations- und Phasenverhalten 163 p. (2014) = Dissertation, Technische Universität Dortmund, 2014 2018-04-1808:50 [IMPULSE-2018-00203] Journal Article et al Impact of oxygen diffusion on superconductivity in $YBa_ 2 Cu _3 O_ { 7 − δ }$ thin films studied by positron annihilation spectroscopy Physical review / B 97(14), 144503 (2018) [10.1103/PhysRevB.97.144503] The oxygen deficiencyδin YBa2Cu3O7−δ(YBCO) plays a crucial role for affecting high-temperature superconductivity. We applied (coincident) Doppler broadening spectroscopy of theelectron-positron annihilation line to study in situ the temperature dependence of the oxygen con-centration and its depth profile in single crystalline YBCO film grown on SrTiO3(STO) substrates.The oxygen diffusion during tempering was found to lead to a distinct depth dependence ofδ, whichis not accessible using X-ray diffraction. [...] 2018-04-1311:47 [IMPULSE-2018-00196] Master Thesis Wendl, A. Neutron Spin Echo Spectroscopy on Geometrically Frustrated Magnets 98 p. (2018) = Masterarbeit, TUM, 2018 In the cubic rare-earth pyrochlore Ho2Ti2 O7 , the magnetic holmium ions sit on a tetraedricrare-earth sublattice and experience strong crystalline electric field effects. The resultingpronounced local h111i-Ising anisotropy, in the combination with ferromagnetic coupling,creates a macroscopically degenerate ground state. [...] 2018-04-1115:50 [IMPULSE-2018-00187] Contribution to a conference proceedings et al The structure-dynamics relationship in binary glass-forming alloy melts The 16th International Conference on Rapidly Quenched & Metastable Materials, Meeting locationLeoben, Österreich, 27 Aug 2017 - 1 Sep 2017 1 pp. (2017) Despite considerable research effort, the mechanisms of glass-formation are not well understood on the atomic length and time scale. While the metallic alloys showing the best glass-forming ability are multi-component alloys, the less complex binary glass-forming systems are attractive for studies aiming to find a microscopic understanding of the glass-formation process [...] 2018-04-1114:50 [IMPULSE-2018-00179] Preprint et al Tunable viscosity modification with diluted particles: When particles decrease the viscosity of complex fluids While spherical particles are the most studied viscosity modifiers, they are well known only to increase viscosities, in particular at low concentrations. Extended studies and theories on non-spherical particles find a more complicated behavior, but still a steady increase. [...] Restricted: PDF; 2018-04-1113:25 [IMPULSE-2018-00175] Preprint et al Field dependence of non-reciprocal magnons in chiral MnSi Spin waves in chiral magnetic materials are strongly influenced by the Dzyaloshinskii-Moriya interaction (DMI) resulting in various intriguing phenomena like non-reciprocal magnon propagation and magnetochiral dichroism. The DMI also stabilizes spatially periodic magnetic textures, in particular, helimagnetic order and skyrmion lattices that naturally give rise to magnon band structures with interesting prospects for magnonics applications. [...] 2018-04-1112:04 [IMPULSE-2018-00168] Preprint et al Liquid-liquid transition revealed by quasi-static cooling of an ultra-viscous metallic liquid Temperature-driven polyamorphism has been reported in various supercooled liquids and glasses. The dynamical and structural routes followed by the system during such crossovers are however not universal and appear to be related to intrinsic kinetic properties of the liquid. [...] Restricted: PDF; 2018-04-1110:57 [IMPULSE-2018-00163] Preprint et al Origin of Ferroelectricity in Orthorhombic $LuFeO_3$ In this Letter, we demonstrate that a small but finite ferroelectric polarization in orthorhombic LuFeO$_3$ is primarily of electronic origin (oriented along a-axis) driven by commensurate (k = 0) and collinear magnetic structure. The nonpolar orthorhombic lattice (space group $Pnma$) undergoes isostructural transition at the magnetic transition temperature $T_N$ ($\sim$600 K). [...] Restricted: PDF; 2018-04-1110:53 [IMPULSE-2018-00162] Preprint et al Uniaxial and hydrostatic pressure effects in $alpha-RuCl_3$ single crystals via thermal-expansion measurements We present high-resolution thermal-expansion and specific-heat measurements of single crystalline alpha-RuCl3. An extremely hysteretic structural transition expanding over 100 K is observed by thermal- expansion along both crystallographic axes, which we attribute to a change of stacking sequence of the RuCl3 layers. [...] Restricted: PDF; 2018-04-1110:51 [IMPULSE-2018-00161] Preprint Hugenschmidt, C. In-situ observation of temperature-dependent segregation of Ni adatoms on oriented Pd surfaces We report the direct observation of the in-situ temperature-dependent surface segregation of Ni adatoms on single crystalline Pd surfaces using Positron annihilation induced Auger Electron Spectroscopy (PAES). For this study, a single atomic layer of Ni was grown on Pd with the crystallographic orientations Pd(111), Pd(110) and Pd(100). [...] Restricted: PDF;