Multi-k magnetic structures in USb_{0.9}Te_{0.1} and UAs_{0.8}Se_{0.2} observed via resonant x-ray scattering at the U M4 edge

Experiments with resonant photons at the U M4 edge have been performed on a sample of USb_{0.9}Te_{0.1}, which has an incommensurate magnetic structure with k = 0.596(2) reciprocal lattice units. The reflections of the form , as observed previously in a commensurate k = 1/2 system [N. Bernhoeft et al., Phys. Rev. B 69 174415 (2004)] are observed, removing any doubt that these occur because of multiple scattering or high-order contamination of the incident photon beam. They are clearly connected with the presence of a 3k configuration. Measurements of the reflections from the sample UAs_{0.8}Se_{0.2} in a magnetic field show that the transition at T* ~ 50 K is between a low-temperature 2k and high-temperature 3k state and that this transition is sensitive to an applied magnetic field. These experiments stress the need for quantitative theory to explain the intensities of these reflections.Comment: submitted to Phys. Rev.

Neutron scattering study of TbPtIn intermetallic compound

Neutron diffraction techniques have been used to study the magnetic properties of a TbPtIn single-crystal as a function of temperature and magnetic field. In the absence of an externally applied magnetic field, the compound orders, below approximately 47 K, in an antiferromagnetic structure with propagation vector k=(12,0,12); the magnetic moments were found to be parallel to the [12̄0] direction. Measurements at 4.2 K, with a magnetic field applied along the [12̄0] direction, revealed metamagnetic transitions at approximately 20 kG and 40 kG

Magnetic structures and excitations in CePd2(Al, Ga)2 series: Development of the "vibron" states

CePd2Al2-xGax compounds crystallizing in the tetragonal CaBe2Ge2-type structure (space group P4/nmm) and undergoing a structural phase transition to an orthorhombic structure (Cmme) at low temperatures were studied by means of neutron scattering. The amplitude-modulated magnetic structure of CePd2Al2 is described by an incommensurate propagation vector k - =(dx, 12+dy, 0) with dx=0.06 and dy=0.04. The magnetic moments order antiferromagnetically within the ab planes stacked along the c axis and are arranged along the direction close to the orthorhombic a axis with a maximum value of 1.5(1) µB/Ce3+. CePd2Ga2 reveals a magnetic structure composed of two components: the first is described by the propagation vector k1 - =(12, 12, 0), and the second one propagates with k2 - =(0, 12, 0). The magnetic moments of both components are aligned along the same direction - the orthorhombic 100] direction - and their total amplitude varies depending on the mutual phase of magnetic moment components on each Ce site. The propagation vectors k1 - and k2 - describe also the magnetic structure of substituted CePd2Al2-xGax compounds, except the one with x=0.1.CePd2Al1.9Ga0.1 with magnetic structure described by k - and k1 - stays on the border between pure CePd2Al2 and the rest of the series. Determined magnetic structures are compared with other Ce 112 compounds. Inelastic neutron scattering experiments disclosed three nondispersive magnetic excitations in the paramagnetic state of CePd2Al2, while only two crystal field (CF) excitations are expected from the splitting of ground state J=52 of the Ce3+ ion in a tetragonal/orthorhombic point symmetry. Three magnetic excitations at 1.4, 7.8, and 15.9 meV are observed in the tetragonal phase of CePd2Al2. A structural phase transition to an orthorhombic structure shifts the first excitation up to 3.7 meV, while the other two excitations remain at almost the same energy. The presence of an additional magnetic peak is discussed and described within the Thalmeier-Fulde CF-phonon coupling (i.e., magnetoelastic coupling) model generalized to the tetragonal point symmetry. The second parent compound CePd2Ga2 does not display any sign of additional magnetic excitation. The expected two CF excitations were observed. The development of magnetic excitations in the CePd2Al2-xGax series is discussed and crystal field parameters determined

Multi-k⃗\vec{k} Configurations

Using resonant x-ray scattering to perform diffraction experiments at the U M$_{4}$ edge novel reflections of the generic form have been observed in UAs$_{0.8}$Se$_{0.2}$ where $\vec{k} = $, with $k = {1/2}$ reciprocal lattice units, is the wave vector of the primary (magnetic) order parameter. The reflections, with $10^{-4}$ of the magnetic intensities, cannot be explained on the basis of the primary order parameter within standard scattering theory. A full experimental characterisation of these reflections is presented including their energy, azimuthal and temperature dependencies. On this basis we establish that the reflections most likely arise from the electric dipole operator involving transitions between the core 3d and partially filled $5f$ states. The temperature dependence couples the peak to the triple-$\vec{k}$ region of the phase diagram: Below $\sim 50$ K, where previous studies have suggested a transition to a double-$\vec{k}$ state, the intensity of the $$ is dramatically reduced. Whilst we are unable to give a definite explanation of how these novel reflections appear, this paper concludes with a discussion of possible ideas for these reflections in terms of the coherent superposition of the 3 primary (magnetic) order parameters

Variation in the Glucose Transporter gene <i>SLC2A2 </i>is associated with glycaemic response to metformin

Metformin is the first-line antidiabetic drug with over 100 million users worldwide, yet its mechanism of action remains unclear1. Here the Metformin Genetics (MetGen) Consortium reports a three-stage genome-wide association study (GWAS), consisting of 13,123 participants of different ancestries. The C allele of rs8192675 in the intron of SLC2A2, which encodes the facilitated glucose transporter GLUT2, was associated with a 0.17% (P = 6.6 × 10−14) greater metformin-induced reduction in hemoglobin A1c (HbA1c) in 10,577 participants of European ancestry. rs8192675 was the top cis expression quantitative trait locus (cis-eQTL) for SLC2A2 in 1,226 human liver samples, suggesting a key role for hepatic GLUT2 in regulation of metformin action. Among obese individuals, C-allele homozygotes at rs8192675 had a 0.33% (3.6 mmol/mol) greater absolute HbA1c reduction than T-allele homozygotes. This was about half the effect seen with the addition of a DPP-4 inhibitor, and equated to a dose difference of 550 mg of metformin, suggesting rs8192675 as a potential biomarker for stratified medicine

Structural Phase Transition in CeCuAl3CeCuAl_{3} Single Crystal

The high temperature properties of $CeCuAl_{3}$ single crystal were investigated by differential scanning calorimetry and high-temperature x-ray diffraction. The structural phase transition takes place around 300 °C. The phase transition changes the structural parameters only, the tetragonal $BaNiSn_{3}$-type structure is preserved. The significant changes of lattice parameters and especially atomic fraction coordinates with this transition are discussed with respect to the number of heating/cooling cycles and stability in time. Magnetic properties of as-cast and annealed sample are shown for comparison

Lattice Heat Capacity in RTAl (R = Y, Lu; T = Ni, Cu, Pd) Compounds

We present analysis of the specific heat of the RTAl (R = Y, Lu; T = Cu, Ni, Pd) compounds. We focus on the lattice contribution and analyze the dependence of all the characteristic parameters in the Debye and Einstein models on the atomic masses and interatomic distances

Magnetic Order in TbPdIn

The magnetic structure in TbPdIn was investigated by neutron diffraction experiments. The results reveal a long-range magnetic structure with propagation vector (0,0,0) and the Tb moments forming a non-collinear structure within the basal plane that is unchanged over the whole temperature region below the ordering temperature of 66 K