Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering

We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30 multilayer with ultrathin Fe layers and nominal thickness of the chromium spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation. The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has been detected at zero external field. The joint fit of the reflectivity curves and Mossbauer spectra of reflectivity measured near the critical angle and at the "magnetic" peak reveals that the magnetic structure of the multilayer is formed by two spirals, one in the odd and another one in the even iron layers, with the opposite signs of rotation. The double-spiral structure starts from the surface with the almost antiferromagnetic alignment of the adjacent Fe layers. The rotation of the two spirals leads to nearly ferromagnetic alignment of the two magnetic subsystems at some depth, where the sudden turn of the magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to rotate in opposite directions. The observation of this unusual double-spiral magnetic structure suggests that the unique properties of giant magneto-resistance devices can be further tailored using ultrathin magnetic layers.Comment: 9 pages, 3 figure

Автоматизированная система построения оптимальных моделей внедрения энергосберегающих в учреждениях образования

Питання аналізу ефективності використання енергетичних ресурсів для бюджетної сфери є актуальними, по-перше, через зношеність фонду будівель, по-друге, через відсутність бюджетного фінансування на покриття комунальних витрат і проведення заходів з енергозбереження та санації будівель. Для розробки та реалізації галузевих програм з енергоефективності, необхідна розробка методики оцінки стану енергетичних господарств ВНЗ та їх будівель та рівня ефективності використання енергії в них, яка дозволить за невеликого об’єму фінансування визначати об’єкти, що потребують першочергової реалізації заходів з енергоефективності. Для вирішення проблеми побудови оптимальної моделі енергозберігаючих заходів підприємства з урахуванням фінансових обмежень пропонується використання методологічного апарату штучних імунних систем. Пропонується алгоритм із застосуванням еволюційних методів штучних імунних систем для синтезу оптимальних моделей впровадження енергозберігаючих заходів у ВНЗ, який був реалізований у автоматизованій системі прийняття рішень комплексної програми енергозбереження у галузі освіти.Question analysis of efficiency of use of energy resources acutely in the public sector, firstly, because of the depreciation of the building stock, and secondly, due to the lack of budget funding to cover utility costs and activities on energy conservation and rehabilitation of buildings. For the development and implementation of sectoral programs on energy efficiency, the need to develop methodologies for evaluating the state of the energy sector and university buildings and the level of energy efficiency in them that would allow a short time and with a small amount of funding to identify items that require priority implementation energy efficiency measures. To solve the problem of constructing an optimal model of energy saving measures on the basis of enterprise financial constraints proposed methodological apparatus using artificial immune systems. On this basis, the algorithm has been developed using evolutionary techniques of artificial immune systems for the synthesis of optimal models of energy efficiency measures in universities, which was implemented in the automated decision-making system of comprehensive energy efficiency programs in the field of education.Вопросы анализа эффективности использования энергетических ресурсов для бюджетной сфере актуальны, во-первых, из-за изношенности фонда зданий, во-вторых, из-за отсутствия бюджетного финансирования на покрытие коммунальных расходов и проведение мероприятий по энергосбережению и санации зданий. Для разработки и реализации отраслевых программ по энергоэффективности, необходима разработка методики оценки состояния энергетических хозяйств вузов и их зданий и уровня эффективности использования энергии в них, которая бы позволила в короткие сроки и небольшого объема финансирования определять объекты, требующие первоочередной реализации мероприятий по энергоэффективности. Для решения проблемы построения оптимальной модели энергосберегающих мероприятий предприятия с учетом финансовых ограничений предлагается использование методологического аппарата искусственных иммунных систем. На этой базе был разработан алгоритм с применением эволюционных методов искусственных иммунных систем для синтеза оптимальных моделей внедрения энергосберегающих мероприятий в вузе, который был реализован в автоматизированной системе принятия решений комплексной программы энергосбережения в области образования

Microstructure and magnetoresistance of Co90Fe10/Cu and Co65Fe26Ni9/Cu multilayers

Investigations of the microstructure, magnetic and magnetotransport properties of the optimized [Co90Fe10/Cu]n and [Co65Fe26Ni9/Cu] n multilayers with n = 32 prepared by magnetron sputtering are performed. These nanostructures exhibit the magnetoresistance values 83 % and 36 % at room temperature, respectively. The article presents the results of the influence of Co65Fe26Ni9 alloy on the magnetoresistance values and crystal structure of multilayers. In the periodic part of the nanostructure [Co65Fe26Ni9/Cu] n based on CoFeNi ternary alloy, besides fcc the formation of a bcc phase in the continuous boundaries around crystallites is found. © Published under licence by IOP Publishing Ltd

Structural State and Magnetic Properties of Nd2Fe14B-Type Rapidly Quenched Alloys

Using the X-ray, elastic neutron diffraction (END) and small angular neutron scattering (SANS) methods (Diffractometers D2 and D3 respectively), transmitting electronic microscopy (JEOL JEM-200CX) and magnetometry technique (vibrating sample magnetometer - VSM) the structure and magnetic properties of the rapidly quenched (RQ) alloys of the following compositions: A) Nd14Fe78B8; B) Y12Fe82B6; C) Nd13.3Co6.6Fe72.6Ge0.9B6.6; D)Nd9Fe85B6; E) Nd9Fe79B12; F) Nd9Fe74Ti4CB12 have been studied. At some quenching conditions or after consequent heat treatments of these alloys the nanoscale state of the main 2-14-1 phase and α-Fe grains can be formed. Their size depends on the sample-preparation conditions and lies in the interval of 10-200 nm. Their influence on magnetic properties of alloys under study is discussed. © 2006 Central Iron and Steel Research Institute.This work was supported by the RF Science and Innovations Agency for Priority, Direction Program "Industry of nanosystems and materials" (Project IN-12.3/00l) and partly by High School Science Potential Development Program (project RNP 2.1.1. 6945)

СОВРЕМЕННАЯ СТРАТЕГИЯ ЗАЩИТНЫХ И МЕДИЦИНСКИХ МЕРОПРИЯТИЙ ПРИ РАДИАЦИОННЫХ АВАРИЯХ

A review of the complex of health protection and medical measures ensuring the prevention of deterministic and reducing the probability of stochastic effects of irradiation during radiation accidents is presented. It is shown that the most effective methods of ensuring radiation safety at radiation accidents are protection by time, protection by distance and shielding of the irradiated object. Medical means of anti-radiation protection are used in addition to collective and individual technical means when it is impossible to avoid over-standard radiation exposure. Classification of antiradiation medicines, including radioprotectors, means for stimulating the radioresistance of the organism, means for preventing and stopping the primary reaction to irradiation, means for preventing and treating injures from irradiation by incorporated radionuclides, means for treating acute bone marrow syndrome, and means for treating local radiation injures of the skin and mucous are given. The list of medical means of antiradiation protection registered in the Russian Federation is presented. Characteristics of first-aid kits, medical bags, medical equipment kits, medical evacuation devices intended for the first aid and medical assistance in the outbreak of a radiation accident and at the stages of medical evacuation are given. The nomenclature of medicines and volumes of the reserve of the Ministry of Health of the Russian Federation intended for liquidation of consequences of emergency situations of radiation nature are given. It is concluded that the Russian Federation has developed and implemented a modern strategy to protect personnel, rescuers and the population in emergency situations of radiation nature, including organizational, technical, hygienic and medical measures in the outbreak of a radiation accident and at the stages of medical evacuation.Представлен обзор комплекса защитных и медицинских мероприятий, обеспечивающих недопущение детерминированных и снижение вероятности стохастических эффектов облучения при радиационных авариях. Показано, что наиболее эффективными способами обеспечения радиационной безопасности в условиях радиационной аварии являются защита временем, защита расстоянием и защита экранированием облучаемого объекта. Медицинские средства противорадиационной защиты применяются в дополнение к коллективным и индивидуальным техническим средствам при невозможности избежать сверхнормативного облучения. Дана классификация противолучевых лекарственных средств, включающая радиопротекторы, средства стимуляции радиорезистентности организма, средства профилактики и купирования первичной реакции на облучение, средства профилактики и лечения поражений от облучения инкорпорированными радионуклидами, средства лечения острого костномозгового синдрома, средства лечения местных лучевых поражений кожи и слизистых оболочек. Представлен перечень медицинских средств противорадиационной защиты, зарегистрированных на территории Российской Федерации. Дана характеристика аптечек первой помощи, сумок медицинских, комплектов медицинского имущества, средств медицинской эвакуации, предназначенных для оказания первой и медицинской помощи в очаге радиационной аварии и на этапах медицинской эвакуации. Приведена номенклатура лекарственных препаратов и объемы резерва Министерства здравоохранения РФ, предназначенных для ликвидации последствий чрезвычайных ситуаций радиационной природы. Сделан вывод о том, что в Российской Федерации разработана и внедрена современная стратегия защиты персонала, спасателей и населения при радиационных авариях, включающая проведение организационных, технических, санитарно-гигиенических и лечебно-профилактических мероприятий в очаге и на этапах медицинской эвакуации

Tunable Spin-Flop Transition in Artificial Ferrimagnets

Spin-flop transition (SFT) consists in a jump-like reversal of antiferromagnetic (AF) lattice into a noncollinear state when the magnetic field increases above the critical value. Potentially the SFT can be utilized in many applications of a rapidly developing AF spintronics. However, the difficulty of using them in conventional antiferromagnets lies in (a) too large switching magnetic fields (b) the need for presence of a magnetic anisotropy, and (c) requirement to apply magnetic field along the correspondent anisotropy axis. In this work we propose to use artificial ferrimagnets (FEMs) in which the SFT occurs without anisotropy and the transition field can be lowered by adjusting exchange coupling in the structure. This is proved by experiment on artificial Fe-Gd FEMs where usage of Pd spacers allowed us to suppress the transition field by two orders of magnitude. © 2021 authors. Published by the American Physical Society. Open access publication funded by the Max Planck Society.We thank A. B. Drovosekov, D. I. Kholin, and D. Cortie for fruitful discussion of the results. This work is partially based on experiments performed at the NREX instrument operated by the Max Planck Society at the MLZ, Garching, Germany and supported by the Deutsche Forschungsgemeinschaft (Project No. 107745057-TRR80). Research in Ekaterinburg was performed within the state assignment of Minobrnauki of Russia (theme “Spin” No. AAAA-A18-118020290104-2) and was partly supported by Russian Foundation for Basic Research (Project No. 19-02-00674)

Structure and magnetic properties of the Co2FeAl and Co2NiSi Heusler alloy films

The structural and magnetic properties (field dependences of the magnetization in magnetic fields of up to 6 kOe) of thin-film Co2FeAl, and Co2NiSi Heusler alloys grown by pulsed laser deposition on glass and a single-crystalline Al2O3 R-plane substrate at different growth temperatures (20, 280 and 420 °C) were studied. It was found that the stoichiometric composition of the films depends on the substrate temperature during growth and repeats the composition of the target for films grown at low temperatures. The films deposited on a single crystalline Al2O3 substrate have uniaxial magnetic anisotropy in the plane. © Published under licence by IOP Publishing Ltd.This work was partly supported by the state assignment of Minobrnauki of Russia (themes “Spin” No. АААА-А18-118020290104-2), RFBR grants (Nos. 18-32-00686 and 18-02-00739) and the Government of the Russian Federation (state contract No. 02.A03.21.0006)

PhenoImageShare:an image annotation and query infrastructure

BACKGROUND: High throughput imaging is now available to many groups and it is possible to generate a large quantity of high quality images quickly. Managing this data, consistently annotating it, or making it available to the community are all challenges that come with these methods. RESULTS: PhenoImageShare provides an ontology-enabled lightweight image data query, annotation service and a single point of access backed by a Solr server for programmatic access to an integrated image collection enabling improved community access. PhenoImageShare also provides an easy to use online image annotation tool with functionality to draw regions of interest on images and to annotate them with terms from an autosuggest-enabled ontology-lookup widget. The provenance of each image, and annotation, is kept and links to original resources are provided. The semantic and intuitive search interface is species and imaging technology neutral. PhenoImageShare now provides access to annotation for over 100,000 images for 2 species. CONCLUSION: The PhenoImageShare platform provides underlying infrastructure for both programmatic access and user-facing tools for biologists enabling the query and annotation of federated images. PhenoImageShare is accessible online at http://www.phenoimageshare.org