Structural disorder versus chiral magnetism in Cr1/3_{1/3}NbS2_2

The crystal structure of a disordered form of Cr$_{1/3}$NbS$_2$ has been characterized using diffraction and inelastic scattering of synchrotron radiation. In contrast to the previously reported symmetry (P6$_3$22), the crystal can be described by a regular twinning of an average P6$_3$ structure with three disordered positions of the Cr ions. Short-range correlations of the occupational disorder result in a quite intense and structured diffuse scattering; a static nature of the disorder was unambiguously attributed by the inelastic x-ray scattering. The diffuse scattering has been modeled using a reverse Monte-Carlo algorithm assuming a disorder of the Cr sub-lattice only. The observed correlated disorder of the Cr sub-lattice reduces the temperature of the magnetic ordering from 130 K to 88 K and drastically modifies the field dependence of the magnetization as it is evidenced by the SQUID magnetometery. We conclude, that in contrast to the helicoidal spin structure assumed for P6$_3$22 form, the compound under study is ferromagnetically ordered with a pronounced in-plane anisotropy

Graded magnonic index and spin wave fano resonances in magnetic structures: Excite, direct, capture

This is the author accepted manuscript. The final version is available from Pan Stanford via the DOI in this record Starting from the general topic and fundamentals of magnonics, we discuss and provide demonstrations of exciting new physics and technological opportunities associated with the graded magnonic index and spin wave Fano resonances, highlighting them as the next big thing in magnonics research.Engineering and Physical Sciences Research Council (EPSRC)European Union Horizon 202

Broadband conversion of microwaves into propagating spin waves in patterned magnetic structures

We have used time-resolved scanning Kerr microscopy and micromagnetic simulations to demonstrate that, when driven by the spatially uniform microwave field, the edges of patterned magnetic samples represent both efficient and highly tunable sources of propagating spin waves. The excitation is due to the local enhancement of the resonance frequency induced by the non-uniform dynamic demagnetizing field generated by precessing magnetization aligned with the edges. Our findings represent a crucial step forward in the design of nanoscale spin-wave sources for magnonic architectures and are also highly relevant to the understanding and interpretation of magnetization dynamics driven by spatially uniform magnetic fields in patterned magnetic samples

Homogeneous and Goldstone modes of spin excitations in Cr

Contributions of homogeneous and Goldstone modes of the spin precession were distinguished in FMR spectra of Cr1/3NbS2 chiral helimagnet. The resonance field of homogeneous mode is determined by uniaxial magnetic anisotropy. The resonance field of Goldstone mode is determined by six-fold anisotropy in basal plane. For the first time, it has been shown experimentally that effective excitation of Goldstone mode is realized only when microwave magnetic field vector h is perpendicular to wave vector of magnetic structure Q

ПОДАТКОВИЙ ТИСК ЯК ДЕСТИМУЛЮЮЧИЙ ЧИННИК РОЗВИТКУ СІЛЬСЬКОГОСПОДАРСЬКОГО ВИРОБНИЦТВА В УКРАЇНІ

Urgency of the research. Agricultural development objectively leads to increasing investments in production. The growth of equity capital of agrarian enterprises is an important factor in increasing economic efficiency of production. Target setting. Important is the study of the investment component of the state taxation policy to agrarian industry performance as well as the impact of state administrative and financial methods of tax pressure on the formation of own funds of enterprises through the use of tax privileges, simplified taxation system, application of special regimes of payment of VAT mode, etc. Actual scientific researches and issues analysis. Definition of special taxation mechanisms for agricultural producers take place against the backdrop of the development of the legal and regulatory framework for the regulation of economic relations are analyzed in works by V. Zbarskyi, V. Matsybora, M. Kucheryavenko, V. Kurylo, V. Mushhenok and others. Uninvestigated parts of general matters defining. To study the features tendencies and features of the tax leverage effect in the system of taxation of agricultural producers in Ukraine. The research objective. To study the current state of legal regulation of the impact of tax burden on agrarian producers and to formulate proposals for improving domestic tax legislation. The statement of basic materials. It is necessary to preserve the application of the VAT regime in the field of agriculture in the wording that existed until January 1, 2016. Let us define the peculiarities of the taxation strategy and the reduction of tax pressure to agricultural payers. Conclusions. The positive impact of the economic investments in the agricultural production sector, though the described benefits in the tax system would be especially noticeable in conditions of limited budgetary subsidies, economic inefficiency of bank credits, rising prices for inputs and other forms of financial crisis.Актуальність теми дослідження. Забезпечення сталого розвитку сільського господарства потребує радикального перетворення економічних відносин. Збільшення власного капіталу аграрних підприємств є важливим фактором підвищення економічної ефективності виробництва. Постановка проблеми. Важливим є дослідження інвестиційної складової державної податкової політики для діяльності аграрної галузі у частині використання податкових пільг, спрощеної системи оподаткування , застосування спеціальних режимів сплати ПДВ, а також впливу державних адміністративних та фінансових методів податкового тиску на формування власних коштів підприємств. Аналіз останніх досліджень і публікацій. Визначення спеціальних механізмів оподаткування для аграріїв на тлі розробки нормативно-правової бази регулювання економічних відносин проаналізовані в роботах В. Збарського, В. Мацибори, М. Кучерявенка, В. Курила, В. Мушенка та ін. Виділення недосліджених частин загальної проблеми. У той же час недостатньо наукових праць висвітлюють тенденції та особливості впливу податкових важелів системи оподаткування на аграріїв в Україні. Постановка завдання. Розгляд сучасного стану правового регулювання впливу податкового тягаря на аграрних виробників та сформульовані пропозиції щодо вдосконалення національного податкового законодавства. Виклад основного матеріалу. Визначено, що для припинення економічного спаду в аграрній галузі в даний час необхідно зберегти застосування режиму ПДВ у сфері сільського господарства в редакції, яка існувала до 1 січня 2016 року. Визначено перспективи стратегії оподаткування та зменшення податкового тиску на аграрних платників податків. Висновки. Вплив економічних інвестицій на аграрну галузь через пільги у системі оподаткування стане відчутним в умовах обмеженості бюджетних дотацій, економічної неефективності банківських кредитів, зростанні цін на матеріально-технічні ресурси та при інших проявах фінансової кризи

(S)-(-)-(2-MeBu)N(Pr)2MeI Salt as Template in the Enantioselective Synthesis of the Enantiopure Two-Dimensional (S)-(-)-(2-MeBu)N(Pr)2Me[\LambdaMnΔCr(C2O4)3] Ferromagnet

We describe herein the synthesis of (rac)- or enantiopure (S)-(-)-(2-MeBu)N(Pr)2MeI ammonium salts. These racemic and enantiopure ammonium salts were used as cationic templates to obtain new two-dimensional (2D) ferromagnets [(rac)-(2-MeBu)N(Pr)2Me][MnCr(C2O4)3] and [(S)-(-)-(2-MeBu)N(Pr)2Me][ΔMn\Lambda nCr(C2O4)3]. The absolute configuration of the hexacoordinated Cr(III) metallic ion in the enantiopure 2D network was determined by a circular dichroism measurement. The structure of [(2-MeBu)N(Pr)2Me][MnCr(C2O4)3], established by single crystal X-ray diffraction, belongs to the chiral P63 space group. According to direct current (dc) magnetic measurements, these compounds are ferrromagnets with a temperature Tc = 6°K. Chirality 25:444\textendash448, 2013. \textcopyright 2013 Wiley Periodicals, Inc

Experimental and theoretical study of the influence of peripheral environment on magnetic properties of tetranuclear manganese skeleton in new representatives of calix[4]arene-containing [MnII2 MnIII2] clusters

A new representative of calix[4]arene-containing tetranuclear manganese complexes of [Mn2IIIMn2II] type with 2,2′-dipyridyl bidentate ligand coordinated in the equatorial plane of the complex (II) has been obtained. The complex is crystallized in monoclinic space group P21/c (a = 14.9402(7) Å, b = 32.816(1) Å, c = 21.595(1) Å, β = 106.888(4)). Its magnetic properties have been studied by the method of SQUID magnetometry. The substitution of a peripheral ligand was shown to influence substantially on the structure of the central fragment of the metal complex, and, hence, on the magnetic properties. Quantum-chemical calculations were performed for this complex and for the similar calix[4]arene-containing manganese complex with pyridine ligand (I). The influence of peripheral environment on the magnetic properties of tetranuclear manganese skeleton was elucidated for both complexes