265 research outputs found

    Prediction for new magnetoelectric fluorides

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    We use symmetry considerations in order to predict new magnetoelectric fluorides. In addition to these magnetoelectric properties, we discuss among these fluorides the ones susceptible to present multiferroic properties. We emphasize that several materials present ferromagnetic properties. This ferromagnetism should enhance the interplay between magnetic and dielectric properties in these materials.Comment: 12 pages, 4 figures, To appear in Journal of Physics: Condensed Matte

    Methodological aspects of the use of dry components of chicken eggs for feeding children with phenylketonuria

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    Currently, one of the most important tasks facing science and production is the creation of functional product technologies for use in different diets of the population in order to preserve and improve health, as well as reduce the risks and consequences of various diseases, including hereditary ones, such as phenylketonuria (PKU). The All-Russian Research Institute of Starch Products develops technologies for the production of low-protein starch-based products/semi-products enriched with functional ingredients and intended for therapeutic nutrition of patients with PKU. As part of the pilot production, the production of these products is organized. Purpose of work:to justify the possibility of using dry components of chicken eggs (melange, protein, yolk) to enrich low-protein starch products (noodles, vermichel, «spider») intended for feeding children over 3 years old with phenylketonuria;evaluate organoleptic properties and efficiency of low-protein starch products enriched in hypophenylalanine diet of patients with phenylketonuria older than 3 years

    Temperature-Dependent Magnetoelectric Effect from First Principles

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    We show that nonrelativistic exchange interactions and spin fluctuations can give rise to a linear magnetoelectric effect in collinear antiferromagnets at elevated temperatures that can exceed relativistic magnetoelectric responses by more than 1 order of magnitude. We show how symmetry arguments, ab initio methods, and Monte Carlo simulations can be combined to calculate temperature-dependent magnetoelectric susceptibilities entirely from first principles. The application of our method to Cr2O3 gives quantitative agreement with experiment.

    The ionization of Mg by electron impact at 1000 eV studied by (e, 2e) experiments

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    The ionization of Mg 3s and 2p and He 1s has been studied in (e, 2e) experiments at about 1000 eV incident energy and 20 eV ejected electron energy for a momentum transfer between 0.5 and 2.1 au. The comparison with the predictions of the distorted wave Born approximation model shows a generally good agreement between experiment and theory. The differences observed between the He and Mg angular distributions can be explained as an initial state effect and are attributed to the differences between the He 1s and Mg 3s wavefunctions in the momentum space

    Solution of the problem of catastrophic relaxation of homogeneous spin precession in superfluid 3^3He-B

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    The quantitative analysis of the "catastrophic relaxation" of the coherent spin precession in 3^3He-B is presented. This phenomenon has been observed below the temperature about 0.5 Tc_c as an abrupt shortening of the induction signal decay. It is explained in terms of the decay instability of homogeneous transverse NMR mode into spin waves of the longitudinal NMR. Recently the cross interaction amplitude between the two modes has been calculated by Sourovtsev and Fomin \cite{SF} for the so-called Brinkman-Smith configuration, i.e. for the orientation of the orbital momentum of Cooper pairs along the magnetic field, LH{\bf L}\parallel {\bf H}. In their treatment, the interaction is caused by the anisotropy of the speed of the spin waves. We found that in the more general case of the non-parallel orientation of L{\bf L} corresponding to the typical conditions of experiment, the spin-orbital interaction provides the additional interaction between the modes. By analyzing experimental data we are able to distinguish which contribution is dominating in different regimes.Comment: 6 pages, 1 figure, submited to JETP letter

    Weak ferromagnetism and field-induced spin reorientation in K2V3O8

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    Magnetization and neutron diffraction measurements indicate long-range antiferromagnetic ordering below TN=4 K in the 2D, S=1/2 Heisenberg antiferromagnet K2V3O8. The ordered state exhibits ``weak ferromagnetism'' and novel, field-induced spin reorientations. These experimental observations are well described by a classical, two-spin Heisenberg model incorporating Dzyaloshinskii-Moriya interactions and an additional c-axis anisotropy. This additional anisotropy can be accounted for by inclusion of the symmetric anisotropy term recently described by Kaplan, Shekhtman, Entin-Wohlman, and Aharony. This suggests that K2V3O8 may be a very unique system where the qualitative behavior relies on the presence of this symmetric anisotropy.Comment: 5 pages, 4 ps figures, REVTEX, submitted to PR

    Dzyaloshinsky-Moriya antisymmetric exchange coupling in cuprates: Oxygen effects

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    We revisit a problem of Dzyaloshinsky-Moriya antisymmetric exchange coupling for a single bond in cuprates specifying the local spin-orbital contributions to Dzyaloshinsky vector focusing on the oxygen term. The Dzyaloshinsky vector and respective weak ferromagnetic moment is shown to be a superposition of comparable and, sometimes, competing local Cu and O contributions. The intermediate oxygen 17^{17}O Knight shift is shown to be an effective tool to inspect the effects of Dzyaloshinsky-Moriya coupling in an external magnetic field. We predict the effect of strongstrong oxygen weak antiferromagnetism in edge-shared CuO2_2 chains due to uncompensated oxygen Dzyaloshinsky vectors. Finally, we revisit the effects of symmetric spin anisotropy, in particular, those directly induced by Dzyaloshinsky-Moriya coupling.Comment: 12 pages, 2 figures, submitted to JET

    Magnon BEC in superfluid 3He-A

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    The new mode of magnetization precession in superfluid 3He-A in a squeezed aerogel has been recently reported. We consider this mode in terms of the Bose-Einstein condensation (BEC) of magnons. The difference between magnon BEC states in 3He-A and in 3He-B is discussed.Comment: 6 pages, 2 figures, JETP Letters style, published versio

    The Non-linear Optical Spin Hall Effect and Long-Range Spin Transport in Polariton Lasers

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    We report on the experimental observation of the non-linear analogue of the optical spin Hall effect under highly non-resonant circularly polarized excitation of an exciton polariton condensate in a GaAs/AlGaAs microcavity. Initially circularly polarized polariton condensates propagate over macroscopic distances while the collective condensate spins coherently precess around an effective magnetic field in the sample plane performing up to four complete revolutions
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