Mössbauer effect studies of thin iron films synthesized by ion beam assisted deposition technique

© 2018 Institute of Physics Publishing. All rights reserved. The paper presents the results of Mössbauer effect studies of thin iron films obtained by ion-assisted deposition technique. It was found that the films obtained consist of several phases and have a perpendicular magnetic anisotropy. Magnetization direction can be changed by external magnetic field in sample plane

Magnetic and Mössbauer effect studies of ZnO thin film implanted with iron ions to high fluence

© Published under licence by IOP Publishing Ltd.We present the results of magnetic and Mössbauer effect studies of zinc oxide thin film obtained by RF magnetron sputtering and implanted with 40 keV iron ions to a fluence of 1.5•1017 ion/cm2. As-implanted and post-annealed sample shows ferromagnetic properties at room temperature and consists of paramagnetic and ferromagnetic phases according to Mössbauer spectroscopy

Oxidation and magnetic states of chalcopyrite CuFeS2: A first principles calculation

The ground state band structure, magnetic moments, charges and population numbers of electronic shells of Cu and Fe atoms have been calculated for chalcopyrite CuFeS2 using density functional theory. The comparison between our calculation results and experimental data (X-ray photoemission, X-ray absorption and neutron diffraction spectroscopy) has been made. Our calculations predict a formal oxidation state for chalcopyrite as Cu 1+Fe3+S2 2-. However, the assignment of formal valence state to transition metal atoms appears to be oversimplified. It is anticipated that the valence state can be confirmed experimentally by nuclear magnetic and nuclear quadrupole resonance and Mössbauer spectroscopy methods. © 2014 Pleiades Publishing, Ltd

Coloration of natural beryl by iron ion implantation

Natural colorless crystals of Ural beryl were implanted at room temperature with 40 keV Fe+ ions with fluences in the range of 0.5-1.5×1017 ion/cm2. As-implanted samples show dark-grey tone due to radiation damage of beryl crystal. Subsequent thermal annealing of irradiated crystals in oxygen at 600 °C for 30 min results in the color change, to yellowish or yellow-orange tones with golden luster, depending on value of iron fluence. The nature of beryl coloration was studied by optical absorption, Mössbauer and Rutherford backscattering (RBS) spectroscopes. It was established that the thermal treatment of iron-irradiated beryl lead to inward diffusive redistribution of iron ions. An appearance of optical absorption bands connected with charge-transfers O2-→FeVI 3+ and O2-→FeIV 2+, FeIV 3+ determine the yellow tone in colored beryls. Most of implanted iron ions are founded in both tetrahedral FeIV 2+ and octahedral FeVI 3+ sites where they may substitute beryllium and aluminum host ions by isomorphic way. © 2003 Elsevier Science B.V. All rights reserved

Structural and magnetic studies of thin Fe⁵⁷ films formed by ion beam assisted deposition

© 2016 Elsevier B.V. All rights reserved.Thin Fe57 films with the thickness of 120 nm have been prepared on glass substrates by using the ion-beam-assisted deposition technique. X-ray diffraction, electron microdiffraction and Mössbauer spectroscopy studies have shown that as-deposited films are in a stressful nanostructured state containing the nanoscaled inclusions of α-phase iron with the size of ∼10 nm. Room temperature in-plane and out-of-plane magnetization measurements confirmed the presence of the magnetic α-phase in the iron film and indicated the strong effect of residual stresses on magnetic properties of the film as well. Subsequent thermal annealing of iron films in vacuum at the temperature of 450 °C stimulates the growth of α-phase Fe crystallites with the size of up to 20 nm. However, electron microdiffraction and Mössbauer spectroscopic data have shown the partial oxidation and carbonization of the iron film during annealing. The stress disappeared after annealing of the film. The magnetic behaviour of the annealed samples was characterized by the magnetic hysteresis loop with the coercive field of ∼10 mT and the saturation magnetization decreased slightly in comparison with the α-phase Fe magnetization due to small oxidation of the film

Функциональная оценка левого предсердия с помощью эхокардиографии после радиочастотной абляции устьев легочных вен и левого предсердия у пациентов c хирургическим лечением фибрилляции предсердий и протезированием митрального клапана

Material and methods. A prospective, randomized, single-center study was conducted. It included 166 patients with mitral valve disease divided into three groups depending on types of AF: with paroxysmal AF at 14 (8.4%) patients, with persistent AF at 63 (37, 9%) patients and with long-term persistent AF at 89 (53.6%) patients hospitalized at the Interregional Clinic and Diagnostic Center Kazan from 2011 to 2018. An average age of patients was 57 ± 5 years old, mainly females amounted to 97 (58.4%).Results. Surgical isolation of the pulmonary vein ostia and the left atrium by RFA at mitral valve replacement significantly improves the contractile function of the left atrium, which allows us to judge about the improvement of the transport function of the left heart chambers as a whole.Цель исследования: оценка геометрического, функционального ремоделирования левого предсердия (ЛП) после радиочастотной абляции (РЧА) устьев легочных вен, ЛП у пациентов при протезировании митрального клапана.Материал и методы. Проведено проспективное рандомизированное одноцентровое исследование. В исследование включено 166 пациентов с заболеванием митрального клапана, разделенных на 3 группы в зависимости от длительности фибрилляции предсердий (ФП): с пароксизмальной ФП у 14 (8,4%) пациентов, с персистирующей ФП у 63 (37,9%) пациентов и с длительной персистирующей ФП у 89 (53,6%) пациентов, госпитализированных в Межрегиональный клинико-диагностический центр Казани с 2011 по 2018 г. Средний возраст пациентов составил 57 ± 5 лет, женщин было 97 (58,4%).Результаты. Хирургическая изоляция устьев легочных вены и ЛП с помощью РЧА при замене митрального клапана позволяет восстановить синусовый ритм, что определяет ремоделирование ЛП, таким образом отмечается улучшение транспортной функции левых отделов сердца в целом

NQR/NMR and Mössbauer spectroscopy of sulfides: Potential and versatility

Nuclear quadrupole resonance (NQR), nuclear magnetic resonance (NMR) and nuclear gamma-resonance (NGR or Mössbauer Effect) methods are generally described as highly sensitive tools in studies of local electronic structure and symmetry in solid-state materials. This is due to high informativity in electronic structure investigations, high resolution in phase-structural diagnostics (down to nano-scale), possibility to study polycrystalline and complex compounds, and to the non-destructive character of these methods. As applied to Earth sciences, both NQR/NMR and Mössbauer spectroscopy methods contribute to mineralogical material science and mineral physics. Another important aspect is the fact that these methods, as demonstrated recently, belong to unique techniques suitable for on-line bulk mineralogical analysis. This includes remotely operated sensors used with conveyor systems in mining/materials handling and similar applications where real-time data collection/processing provides significant commercial benefits. These developments open new pathways for NQR/NMR and Mössbauer spectroscopy applications. Notably, NQR/NMR and Mössbauer effects are observed primarily on different nuclei-probes but provide similar information about the local properties of materials (hyperfine fields, electric field gradients and relaxation effects). This makes NQR/NMR and Mössbauer methods mutually complementary despite their significant technical differences. This paper includes examples of recent applications of NQR, NMR and Mössbauer spectroscopic tools to studies of copper-, antimony- and iron-containing sulfides, demonstrating how these methods can contribute to an improved understanding of geochemical problems. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart

Application of 57Fe Mössbauer spectroscopy as a tool for mining exploration of bornite (Cu5FeS4) copper ore

Nuclear resonance methods, including Mössbauer spectroscopy,are considered as unique techniques suitable for remote on-line mineralogical analysis. The employment of these methods provides potentially significant commercial benefits for mining industry. As applied to copper sulfide ores, Mössbauer spectroscopy method is suitable for the analysis noted. Bornite (formally Cu5FeS4) is a significant part of copper ore and identification of its properties is important for economic exploitation of commercial copper ore deposits. A series of natural bornite samples was studied by 57Fe Mössbauer spectroscopy. Two aspects were considered: reexamination of 57Fe Mössbauer properties of natural bornite samples and their stability irrespective of origin and potential use of miniaturized Mössbauer spectrometers MIMOS II for in-situ bornite identification. The results obtained show a number of potential benefits of introducing the available portative Mössbauer equipment into the mining industry for express mineralogical analysis. In addition, results of some preliminary 63,65Cu nuclear quadrupole resonance (NQR) studies of bornite are reported and their merits with Mössbauer techniques for bornite detection discussed. © 2013 Springer Science+Business Media Dordrecht

Magnetic properties of the covalent chain antiferromagnet RbFeSe2

© 2016 American Physical Society.Single crystals of the ternary iron selenide RbFeSe2 have been investigated by means of x-ray diffraction, magnetic susceptibility, magnetization, and specific-heat measurements as well as by Mössbauer spectroscopy. Built up from linear chains of edge-sharing FeSe4 tetrahedra, RbFeSe2 represents a quasi-one-dimensional antiferromagnet. Below TN=248 K three-dimensional antiferromagnetic collinear magnetic order sets in, with the magnetic moments oriented perpendicularly to the chain direction. The hyperfine fields determined from our Mössbauer studies reveal strongly reduced magnetic moments. The high-temperature susceptibility data of RbFeSe2 suggest a one-dimensional metallic character along the chains