Enhanced iron magnetic moment in the ThFe11C2 intermetallic compound

International audienceDetailed theoretical investigations on the electronic and magnetic properties of the ThFe11C2 compound have been performed using both the linear muffin-tin orbital and Korringa-Kohn-Rostocker methods of band structure calculation. The structure of the ThFe11C2 compound has three inequivalent iron sites with different local environment. A strongly enhanced magnetic moment is observed on certain Fe positions, coexisting with much lower magnetic moments on other iron positions of the lattice. Band structure calculations indeed show that the Fe magnetic moments depend strongly on the local environment. The average Fe magnetic moment obtained from these calculations is in good agreement with the experimental average Fe moment obtained from magnetization measurements. The orbital contribution to the magnetic moment is found to be especially large on the Fe 4b position. Comparing calculated hyperfine fields with experimental results, it is found that the calculated and experimental hyperfine fields are correlated. However, similarly to the results reported before for elemental Fe, the magnitude of all calculated Fe hyperfine fields is about 25% smaller. The agreement with the Mössbauer measurements is improved by scaling the core polarization contribution and by estimating the orbital valence d-electrons contribution to the magnetic hyperfine fields using the local spin density approximation + dynamical mean field theory calculated orbital moments

Analysis of Export Demand for Indonesian Agricultural Commodities by the Chinese Market

China is one of the main export destination of Indonesian agricultural commodities. Nevertheless, the export trend of Indonesian agricultural commodities to China during 2012-2016 tend to declined, therefore it is necessary to analyze it. This research aimed to analyze the determinant of Indonesian agricultural commodities export demand by China. Indonesian agricultural commodities export demand was estimated using a regression model on panel data. Panel data in this research consisted of ten data of Indonesian agricultural commodities export to China during 1999-2016 period. The results showed that Indonesian agricultural commodities export demand by China was significantly influenced by real GDP per capita of China, real exchange rate, export price of agricultural commodities and import tariff of agricultural commodities in China.An increasing in real GDP per capita lead an increase in Indonesian agricultural commodities export demand. The depreciation of Rupiah which was expected to increase export demand, but in this research it decreased Indonesian agricultural commodities export demand from China.In addition, Indonesian agricultural commodities export demand tend to increased despite the export prices of agricultural commodities and import tariffs of agricultural commodities in China increased

Analisis Faktor Faktor yang Mempengaruhi Produksi Pembenihan Ikan Lele Dumbo (Clarias Gariepenus) di Kabupaten Wonogiri

This research are for: (1) To analysis the cost and income of Catfish hatchery farm in Wonogiri District. (2) To analysis the influence factors of Catfish hatchery production in Wonogiri District. (3) To analysis the efficiency level of feed production, natural food, and labour. The basic method of the research is description analysis method and the conduct of the research is using a census method. This research had conducted in the district of Wonogiri which consist of 45 respondents, analyzed data included hatchery income, R/C ratio, elasticity, efficiency, and multiple linier regression test. The result of the research showed that the relation between factors and hatchery of Dumbo Catfish production showed in multiple linier regression model, they are : LnP = 7.472 - 0.047LnX1 + 0.312LnX2 + 0.388LnX3 + 0.304LnX4 + 0.136LnX5 + 0.016LnX6 + 0.108LnD1 + 0.058LnD2. The result of the analysis showed the number of broodstock, feed, natural food, labour, hatchery technology and counseling which were significant influenced in Catfish hatchery production, meanwhile the land area and hatchery process were not really influences to the Catfish hatchery production. The result of the research had obtained the income of Catfish hatchery with the price of Rp. 2.369.533,-, value of R/C ratio was 2,67, feed production value, natural food, and labour were >1 which showed inefficient, the elasticity value of all independent variable was elastic

Heralded Noiseless Amplification of a Photon Polarization Qubit

Non-deterministic noiseless amplification of a single mode can circumvent the unique challenges to amplifying a quantum signal, such as the no-cloning theorem, and the minimum noise cost for deterministic quantum state amplification. However, existing devices are not suitable for amplifying the fundamental optical quantum information carrier, a qubit coherently encoded across two optical modes. Here, we construct a coherent two-mode amplifier, to demonstrate the first heralded noiseless linear amplification of a qubit encoded in the polarization state of a single photon. In doing so, we increase the transmission fidelity of a realistic qubit channel by up to a factor of five. Qubit amplifiers promise to extend the range of secure quantum communication and other quantum information science and technology protocols.Comment: 6 pages, 3 figure

Calculating linear response functions for finite temperatures on the basis of the alloy analogy model

A scheme is presented that is based on the alloy analogy model and allows to account for thermal lattice vibrations as well as spin fluctuations when calculating response quantities in solids. Various models to deal with spin fluctuations are discussed concerning their impact on the resulting temperature dependent magnetic moment, longitudinal conductivity and Gilbert damping parameter. It is demonstrated that using the Monte Carlo (MC) spin configuration as an input, the alloy analogy model is capable to reproduce results of MC simulations on the average magnetic moment within all spin fluctuation models under discussion. On the other hand, response quantities are much more sensitive to the spin fluctuation model. Separate calculations accounting for either the thermal effect due to lattice vibrations or spin fluctuations show their comparable contributions to the electrical conductivity and Gilbert damping. However, comparison to results accounting for both thermal effects demonstrate violation of Matthiessen's rule, showing the non-additive effect of lattice vibrations and spin fluctuations. The results obtained for bcc Fe and fcc Ni are compared with the experimental data, showing rather good agreement for the temperature dependent electrical conductivity and Gilbert damping parameter

Preparing food at high altitudes

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Soft X-ray Fermi surface tomography of palladium and rhodium via momentum microscopy

Fermi surfaces of transition metals, which describe all thermodynamical and transport quantities of solids, often fail to be modeled by one-electron mean-field theory due to strong correlations among the valence electrons. In addition, relativistic spin–orbit coupling pronounced in heavier elements lifts the degeneracy of the energy bands and further modifies the Fermi surface. Palladium and rhodium, two 4d metals attributed to show significant spin–orbit coupling and electron correlations, are ideal for a systematic and fundamental study of the two fundamental physical phenomena and their interplay in the electronic structure. In this study, we explored the Fermi surface of the 4d noble metals palladium and rhodium obtained via high-resolution constant initial state momentum microscopy. The complete 3D-Fermi surfaces of palladium and rhodium were tomographically mapped using soft X-ray photon energies from 34 eV up to 660 eV. To fully capture the orbital angular momentum of states across the Fermi surface, the Fermi surface tomography was performed using p- and s- polarized light. Applicability and limitations of the nearly-free electron final state model in photoemission are discussed using a complex band structure model supported by experimental evidence. The significance of spin–orbit coupling and electron correlations across the Fermi surfaces will be discussed within the context of the photoemission results. State-of-the-art fully relativistic Korringa–Kohn–Rostoker (KKR) calculations within the one-step model of photoemission are used to support the experimental results

Temperature Dependence of Relativistic Valence Band Splitting Induced by an Altermagnetic Phase Transition

Altermagnetic (AM) materials exhibit non-relativistic, momentum-dependent spin-split states, ushering in new opportunities for spin electronic devices. While the characteristics of spin-splitting have been documented within the framework of the non-relativistic spin group symmetry, there has been limited exploration of the inclusion of relativistic symmetry and its impact on the emergence of a novel spin-splitting in the band structure. This study delves into the intricate relativistic electronic structure of an AM material, alpha-MnTe. Employing temperature-dependent angle-resolved photoelectron spectroscopy across the AM phase transition, we elucidate the emergence of a relativistic valence band splitting concurrent with the establishment of magnetic order. This discovery is validated through disordered local moment calculations, modeling the influence of magnetic order on the electronic structure and confirming the magnetic origin of the observed splitting. The temperature-dependent splitting is ascribed to the advent of relativistic spin-splitting resulting from the strengthening of AM order in alpha-MnTe as the temperature decreases. This sheds light on a previously unexplored facet of this intriguing material