8 research outputs found
Kataloge kleinräumiger kommunalstatistischer Daten im Vergleich: was können KOSTAT, IRB, Urban Audit?
Der Beitrag stellt zunächst drei Datenkataloge vor, die für deutsche Städte eine kleinräumige Stadtbeobachtung auf Grundlage von untergemeindlichen Daten ermöglichen. Dass es für Stadtteildaten nicht nur eine Sammlung gibt, an der sich alle Städte beteiligen, ist unterschiedlichen Entstehungszusammenhängen geschuldet, in denen auf je verschiedene Anforderungen einzugehen war. Weiter werden Gütekriterien vorgeschlagen, die eine Einschätzung der Qualität derartiger Datensammlungen ermöglichen. Dafür werden aktuell diskutierte Standards und Verhaltenskodizes gesichtet, beurteilt und für die Ansprüche der deutschen Kataloge modifiziert. Schließlich werden die drei Kataloge auf dieser Grundlage beurteilt. Diese Beurteilung erlaubt allen Nutzerinnen und Nutzern untergemeindlicher Daten, die aus mehr als einer Kommune stammen, die Reichweite und Sicherheit ihrer darauf fußenden Analysen besser einschätzen zu können
Unidirectional anisotropy in cubic FeGe with antisymmetric spin-spin-coupling
We report strong unidirectional anisotropy in bulk polycrystalline B20 FeGe
measured by ferromagnetic resonance spectroscopy. Bulk and micron-sized samples
were produced and analytically characterized. FeGe is a B20 compound with
inherent Dzyaloshinskii-Moriya interaction. Lorenz microscopy confirms a
skyrmion lattice at in a magnetic field of 150 mT.
Ferromagnetic resonance was measured at ,
near the Curie temperature. Two resonance modes were observed, both exhibit a
unidirectional anisotropy of in
the primary, and in the secondary
mode, previously unknown in bulk ferromagnets. Additionally, about 25 standing
spin wave modes are observed inside a micron-sized FeGe wedge, measured at room
temperature ( K). These modes also exhibit unidirectional
anisotropy
Giant voltage-induced modification of magnetism in micron-scale ferromagnetic metals by hydrogen charging
Owing to electric-field screening, the modification of magnetic properties in ferromagnetic metals by applying small voltages is restricted to a few atomic layers at the surface of metals. Bulk metallic systems usually do not exhibit any magneto-electric effect. Here, we report that the magnetic properties of micron-scale ferromagnetic metals can be modulated substantially through electrochemically-controlled insertion and extraction of hydrogen atoms in metal structure. By applying voltages of only ~ 1 V, we show that the coercivity of micrometer-sized SmCo5, as a bulk model material, can be reversibly adjusted by ~ 1 T, two orders of magnitudes larger than previously reported. Moreover, voltage-assisted magnetization reversal is demonstrated at room temperature. Our study opens up a way to control the magnetic properties in ferromagnetic metals beyond the electric-field screening length, paving its way towards practical use in magneto-electric actuation and voltage-assisted magnetic storage
Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films
We present phonon dispersions, element-resolved vibrational density of states
(VDOS) and corresponding thermodynamic properties obtained by a combination of
density functional theory (DFT) and nuclear resonant inelastic X-ray scattering
(NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and
thin epitaxial films. We see distinct differences in the VDOS of the
antiferromagnetic (AF) and ferromagnetic (FM) phase which provide a microscopic
proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular
sensitivity to the slight tetragonal distortions present in epitaxial films,
which is not encountered in the AF phase. This results in a notable change in
lattice entropy, which is important for the comparison between thin film and
bulk results. Our calculations confirm the recently reported lattice
instability in the AF phase. The imaginary frequencies at the -point depend
critically on the Fe magnetic moment and atomic volume. Analyzing these non
vibrational modes leads to the discovery of a stable monoclinic ground state
structure which is robustly predicted from DFT but not verified in our thin
film experiments. Specific heat, entropy and free energy calculated within the
quasiharmonic approximation suggest that the new phase is possibly suppressed
because of its relatively smaller lattice entropy. In the bulk phase, lattice
degrees of freedom contribute with the same sign and in similar magnitude to
the isostructural AF-FM phase transition as the electronic and magnetic
subsystems and therefore needs to be included in thermodynamic modeling.Comment: 15 pages, 12 figure
Regionale Standards: Ausgabe 2019
Die "Regionalen Standards" gehen zurück auf die Initiative eines gemeinsamen Arbeitskreises, bestehend aus Vertretern des Statistischen Bundesamtes, der Arbeitsgemeinschaft Sozialwissenschaftlicher Institute e.V. (ASI) und des ADM Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V. Sie stellen ein Angebot für die Forschung in der Bundesrepublik Deutschland dar. Die "Regionalen Standards" beschreiben Gebietsabgrenzungen und Instrumente zur Typisierung von Regionen, wie sie in der Bundesrepublik Deutschland von der amtlichen Statistik und/oder der Markt- und Sozialforschung in gewisser Regelmäßigkeit eingesetzt werden. Zusätzlich werden Datensätze aus unterschiedlichen Quellen vorgestellt, die für die Regionalisierung von Bevölkerungsumfragen genutzt werden können und für die Forschung (teils jedoch mit Einschränkungen) zur Verfügung stehen
Giant voltage-induced modification of magnetism in micron-scale ferromagnetic metals by hydrogen charging
In Situ Raman Cell for High Pressure and Temperature Studies of Metal and Complex Hydrides
The ALICE Transition Radiation Detector: construction, operation, and performance
The Transition Radiation Detector (TRD) was designed and built to enhance the capabilities of the ALICE detector at the Large Hadron Collider (LHC). While aimed at providing electron identification and triggering, the TRD also contributes significantly to the track reconstruction and calibration in the central barrel of ALICE. In this paper the design, construction, operation, and performance of this detector are discussed. A pion rejection factor of up to 410 is achieved at a momentum of 1 GeV/ c in p–Pb collisions and the resolution at high transverse momentum improves by about 40% when including the TRD information in track reconstruction. The triggering capability is demonstrated both for jet, light nuclei, and electron selection