978 research outputs found
Die Anästhesie der Anästhesie: Schmerzmedizin in kulturethischer Perspektive
Zusammenfassung: In einer kulturethischen Perspektive betrachtet, lässt sich Schmerzmedizin als Inbegriff aller Medizin verstehen. Als solche enthält sie zwei Dilemmata: Sehr oft müssen Schmerzen zugefügt werden, um Schmerzen zu lindern; und dies kann nur einer tun, der selbst (relativ) frei ist von Schmerzen. Die berufsnotwendige Apathie oder ‚Anästhesie‘ des Anästhesisten entspricht einerseits einem allgemeinen Wahrnehmungstypus des 20.Jh.: dem kühlen Beobachter. Andererseits ist sie die moderne Variante der ursprünglich religiösen Konstellation von Priester und Krankem bzw. Opfer. Heilung geschieht durch Stellvertretung. Das schwache Ich des Kranken übernimmt im Opfer das starke Ich des Therapeuten. In der Kunst und Literatur des 20.Jh. ist dieser Vorgang vielfach beschrieben und gedeutet worden. Kunst und Kultur selbst können solche therapeutische Stellvertretungsfunktion übernehmen. Was hier geschieht, ist wiederum vor dem Hintergrund einer philosophisch-phänomenologischen Analyse des Schmerzes zu verstehen. Schmerz ist der Verteidigungskampf des Leibes gegen die Gefahr, auf den bloßen physischen Körper reduziert zu werden. In den Klagepsalmen des biblischen Hiob-Buches hat solcher Schmerzausdruck vielfältige Ausdrucksformen gefunden, die auch heute hilfreich sein könne
Parasitic small-moment-antiferromagnetism and non-linear coupling of hidden order and antiferromagnetism in URu2Si2 observed by Larmor diffraction
We report simultaneous measurements of the distribution of lattice constants
and the antiferromagnetic moment in high-purity URu2Si2, using both Larmor and
conventional neutron diffraction, as a function of temperature and pressure up
to 18 kbar. We establish that the tiny moment in the hidden order (HO) state is
purely parasitic and quantitatively originates from the distribution of lattice
constants. Moreover, the HO and large-moment antiferromagnetism (LMAF) at high
pressure are separated by a line of first-order phase transitions, which ends
in a bicritical point. Thus the HO and LMAF are coupled non-linearly and must
have different symmetry, as expected of the HO being, e.g., incommensurate
orbital currents, helicity order, or multipolar order.Comment: 4 pages, 4 figure
Imaging and manipulation of skyrmion lattice domains in Cu2OSeO3
Nanoscale chiral skyrmions in noncentrosymmetric helimagnets are promising
binary state variables in high-density, low-energy nonvolatile memory.
Skyrmions are ubiquitous as an ordered, single-domain lattice phase, which
makes it difficult to write information unless they are spatially broken up
into smaller units, each representing a bit. Thus, the formation and
manipulation of skyrmion lattice domains is a prerequisite for memory
applications. Here, using an imaging technique based on resonant magnetic x-ray
diffraction, we demonstrate the mapping and manipulation of skyrmion lattice
domains in Cu2OSeO3. The material is particularly interesting for applications
owing to its insulating nature, allowing for electric field-driven domain
manipulation.Comment: 4 pages, 3 figure
Crystalline phases in chiral ferromagnets: Destabilization of helical order
In chiral ferromagnets, weak spin-orbit interactions twist the ferromagnetic
order into spirals, leading to helical order. We investigate an extended
Ginzburg-Landau theory of such systems where the helical order is destabilized
in favor of crystalline phases. These crystalline phases are based on periodic
arrangements of double-twist cylinders and are strongly reminiscent of blue
phases in liquid crystals. We discuss the relevance of such blue phases for the
phase diagram of the chiral ferromagnet MnSi.Comment: 6 pages, 5 figures (published version
Uniaxial pressure dependence of magnetic order in MnSi
We report comprehensive small angle neutron scattering (SANS) measurements
complemented by ac susceptibility data of the helical order, conical phase and
skyrmion lattice phase (SLP) in MnSi under uniaxial pressures. For all
crystallographic orientations uniaxial pressure favours the phase for which a
spatial modulation of the magnetization is closest to the pressure axis.
Uniaxial pressures as low as 1kbar applied perpendicular to the magnetic field
axis enhance the skyrmion lattice phase substantially, whereas the skyrmion
lattice phase is suppressed for pressure parallel to the field. Taken together
we present quantitative microscopic information how strain couples to magnetic
order in the chiral magnet MnSi.Comment: 23 pages, includes supplemen
Low-temperature properties of single-crystal CrB
We report the low-temperature properties of B-enriched single-crystal
CrB as prepared from high-purity Cr and B powder by a solid-state
reaction and optical float zoning. The electrical resistivity, ,
Hall effect, , and specific heat, , are characteristic of an
exchange-enhanced Fermi liquid ground state, which develops a slightly
anisotropic spin gap below . This observation is corroborated by the absence of a Curie dependence in
the magnetization for reported in the literature. Comparison of
with , where we infer lattice contributions from
measurements of VB, reveals strong antiferromagnetic spin fluctuations with
a characteristic spin fluctuation temperature
in the paramagnetic state, followed by a pronounced second-order mean-field
transition at , and unusual excitations around . The pronounced anisotropy of above is
characteristic of an easy-plane anisotropy of the spin fluctuations consistent
with the magnetization. The ratio of the Curie-Weiss to the Nel
temperatures, , inferred from the
magnetization, implies strong geometric frustration. All physical properties
are remarkably invariant under applied magnetic fields up to ,
the highest field studied. In contrast to earlier suggestions of local-moment
magnetism our study identifies CrB as a weak itinerant antiferromagnet
par excellence with strong geometric frustration.Comment: 15 pages, 9 figure
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