RKKY interaction in the nearly-nested Fermi liquid

We present the results of analytical evaluation of the indirect RKKY interaction in a layered metal with nearly nested (almost squared) Fermi surface. The final expressions are obtained in closed form as a combination of Bessel functions. We discuss the notion of the ``2k_F'' oscillations and show that they occur as the far asymptote of our expressions. We show the existence of the intermediate asymptote of the interaction which is of the sign-reversal antiferromagnetic type and is the only term surviving in the limit of exact nesting. A good accordance of our analytical formulas with numerical findings is demonstrated until the interatomic distances. The obtained expressions for the Green's functions extend the previous analytical results into the region of intermediate distances as well.Comment: 9 pages, REVTEX, 3 .eps figures, to appear in PRB 1 Oct 199

Spin chirality induced by the Dzyaloshinskii-Moriya interaction and the polarized neutron scattering

We discuss the influence of the Dzyaloshinskii-Moriya (DM) interaction in the Heizenberg spin chain model for the observables in the polarized neutron scattering experiments. We show that different choices of the parameters of DM interaction may leave the spectrum of the problem unchanged, while the observable spin-spin correlation functions may differ qualitatively. Particularly, for the uniform DM interaction one has the incommensurate fluctuations and polarization-dependent neutron scattering in the paramagnetic phase. We sketch the possible generalization of our treatment to higher dimensions.Comment: 4 pages, REVTEX, no figures, references added, to appear in PR

1D Frustrated Ferromagnetic Model with Added Dzyaloshinskii-Moriya Interaction

The one-dimensional (1D) isotropic frustrated ferromagnetic spin-1/2 model is considered. Classical and quantum effects of adding a Dzyaloshinskii-Moriya (DM) interaction on the ground state of the system is studied using the analytical cluster method and numerical Lanczos technique. Cluster method results, show that the classical ground state magnetic phase diagram consists of only one single phase: "chiral". The quantum corrections are determined by means of the Lanczos method and a rich quantum phase diagram including the gapless Luttinger liquid, the gapped chiral and dimer orders is obtained. Moreover, next nearest neighbors will be entangled by increasing DM interaction and for open chains, end-spins are entangled which shows the long distance entanglement (LDE) feature that can be controlled by DM interaction.Comment: 8 pages, 9 figure

Ginzburg-Landau functional for nearly antiferromagnetic perfect and disordered Kondo lattices

Interplay between Kondo effect and trends to antiferromagnetic and spin glass ordering in perfect and disordered bipartite Kondo lattices is considered. Ginzburg-Landau equation is derived from the microscopic effective action written in three mode representation (Kondo screening, antiferromagnetic correlations and spin liquid correlations). The problem of local constraint is resolved by means of Popov-Fedotov representation for localized spin operators. It is shown that the Kondo screening enhances the trend to a spin liquid crossover and suppresses antiferromagnetic ordering in perfect Kondo lattices and spin glass ordering in doped Kondo lattices. The modified Doniach's diagram is constructed, and possibilities of going beyond the mean field approximation are discussed.Comment: 18 pages, RevTeX, 7 EPS figures include

Experimental evaluation of amaranth food products in terms of functional food ingredients

Diet correction according to the nutrition enrichment with physiologically valuable nutrients becomes one of the most important issues. Its solution is possible by inclusion in the formulation of food products of raw materials that are characterized by an increased content of deficient substances, primarily protein, dietary fiber, minerals and vitamins. The amaranth meets the criteria above. The use of amaranth processing products in food technologies makes possible to obtain specialized and functional products. In this case, better to conduct experimental confirmation of the expected effect. Studies have been conducted to evaluate the effect of grain and extrudate of whole grain of Universal Amaranth on laboratory animals. Mature male rat’s stomach, liver, and kidneys served as a study material. The results of histological studies showed an improvement in the digestive system of animals and their general condition when grain and extrude Universal Amaranth was included in the diet

Spin-wave dynamics and exchange interactions in multiferroic NdFe3(BO3)4 explored by inelastic neutron scattering

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Continuous wafer scale graphene on cubic SiC 001

The atomic and electronic structure of graphene synthesized on commercially available cubic SiC 001 Si 001 wafers have been studied by low energy electron microscopy LEEM , scanning tunneling microscopy STM , low energy electron diffraction LEED , and angle resolved photoelectron spectroscopy ARPES . LEEM and STM data prove the wafer scale continuity and uniform thickness of the graphene overlayer on SiC 001 . LEEM, STM and ARPES studies reveal that the graphene overlayer on SiC 001 consists of only a few monolayers with physical properties of quasi freestanding graphene. Atomically resolved STM and micro LEED data show that the top graphene layer consists of nanometersized domains with four different lattice orientations connected through the amp; 12296;110 amp; 12297; directed boundaries. ARPES studies reveal the typical electron spectrum of graphene with the Dirac points close to the Fermi level. Thus, the use of technologically relevant SiC 001 Si 001 wafers for graphene fabrication represents a realistic way of bridging the gap between the outstanding properties of graphene and their application