The phase diagram of the betaine arsenate-phosphate mixed crystal system by measurement of the dielectric hysteresis and current curves

The ferroelectric (FE) betaine arsenate (BA) and the antiferroelectric (AF) betaine phosphate (BP) are structurally very closely related and mixed crystals of BAxBP1-x can be grown over the whole concentration range. The concentration (x) – temperature (T) – pressure (P) phase diagram of the system is characterized by a transition from an AF to a FE phase along with the appearance of some mixed regions on changing concentration. Depending on concentration, one or two relaxation processes appear in the low temperature region of the phase diagram. Measurement of the hysteresis loops and the current curves have been carried out along the (x-T-P)-phase diagram of this system. Multiple loops have been observed in various regions of the phase diagram. The correlation of the different contributions of the polarization and the temperature behavior of their critical fields with the main features of the temperature and frequency dependent dielectric constant enables clarification of the rich phase diagram obtained in this mixed compounds in terms of the ferro- and/or antiferroelectric interactions

Raman and infrared study of the quasi-one-dimensional betaine arsenate-phosphate mixed-crystal system

Ferroelectric (FE) betaine arsenate (BA) and antiferroelectric (AF) betaine phosphate (BP) are structurally very closely related and mixed crystals BA(x)BP(1-x) can be grown over the full concentration range. This system exhibits interesting pressure-temperature-concentration phase diagrams in which the transition in concentration from an AF to a FE phase can be observed with a concentration-dependent appearance of some mixed regions. At low temperatures different relaxation processes have been observed that might be related to the transition from a domain state to an orientational glass depending on concentration. In some regions of the phase diagram different phases coexist. The origin of the different transitions and relaxation processes is still unclear and recent x-ray-diffraction studies reveal that the peculiar behavior of the mixed crystals cannot be explained from the structural point of view. We have performed Raman and infrared investigation of samples across the whole (x, T) phase diagram, at various hydrostatic pressures, in order to shed light on the structural origin of the different processes. It is concluded that the FE or AF character of the ordered phase is related to the degrees of freedom of the AsO4 and PO4 tetrahedra. In the same way these units determine the type and the modes triggering the phase transitions for each concentration. The latter seems to occur together with a participation of the betaine molecule, especially of the methyl and buthyl groups.info:eu-repo/semantics/publishedVersio

Ferroelectric/antiferroelectric phase coexistence in the intermediate concentration regions of the BA(x)BP(1-x) phase diagram

Temperature and frequency dependent hysteresis loop measurements have been carried out along the phase diagram of ferroelectric (FE) betaine at-senate (BA) and antiferroelectric (AF) betaine phosphate (BP) mixed crystal system (BA(x)BP(1-x)). Coexistence regions characterized by competing ferro- and/or antiferroelectric interactions are detected by multiple hysteresis loops.(undefined

Far-infrared spectroscopy investigation and lattice dynamics simulations in CsCdBr3 and CsCdBr3: R3+ crystals

Polarized infrared reflectivity spectra of CsCdBr3 crystal were measured at temperatures 20 and 300 K in the wave number range of 10-650 cm-1. Frequencies and damping of the optically active lattice modes at the Brillouin zone center were determined. The lattice dynamics of CsCdBr3 crystal is studied in the framework of the rigid ion model, the phonon density of states, and the spectral representations of correlation functions of relative displacements of a Cd2+ ion and the nearest neighbor Br- ions in the perfect lattice are presented. The local dynamics of the lattice containing impurity rare-earth ions that form symmetrical pair centers substituted for three adjacent Cd2+ ions is analyzed with the formalism of lattice Green's functions. It is argued that resonance and localized vibrations whose frequencies lie near the boundary of the continuous phonon spectrum of a perfect lattice are induced in CsCdBr3: R3+ crystals. The corresponding vibronic satellites have been found in the optical spectra of symmetrical dimers in CsCdBr3: Yb3+, CsCdBr3: Tm3+, and CsCdBr3: Pr3+ single crystals

Not just another genome

Sequence analysis of the Daphnia pulex genome holds some surprises that could not have been anticipated from what was learned so far from other arthropod genomes. It establishes Daphnia as an eco-genetical model organism par excellence

D6.7 Report on the experience of conducting the case studies

One of the main aims of the case studies was to publish improved market reports. The data collected as part of the six case studies have been, or will shortly be, published in the five improved national organic market reports and one first regional market report (MOAN case study). This will make a contribution towards filling the many gaps that continue to exist in organic market data collection in Europe

Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%

Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−

The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

Search for CP violation in D+→K−K+π+D^{+} \to K^{-}K^{+}\pi^{+} decays

A model-independent search for direct CP violation in the Cabibbo suppressed decay $D^+ \to K^- K^+\pi^+$ in a sample of approximately 370,000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35 pb$^{-1}$. The normalized Dalitz plot distributions for $D^+$ and $D^-$ are compared using four different binning schemes that are sensitive to different manifestations of CP violation. No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.

Measurement of the relative rate of prompt χc0, χc1 and χc2 production at √s=7TeV

Prompt production of charmonium χc0, χc1 and χc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √s=7TeV. The χc mesons are identified through their decay to J/ψγ, with J/ψ→μ+mu− using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χc1 and χc2 in the rapidity range 2.0<y<4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χc0 meson production at a hadron collider is also presented