Quantum states and linear response in dc and electromagnetic fields for charge current and spin polarization of electrons at Bi/Si interface with giant spin-orbit coupling

An expansion of the nearly free-electron model constructed by Frantzeskakis, Pons and Grioni [Phys. Rev. B {\bf 82}, 085440 (2010)] describing quantum states at Bi/Si(111) interface with giant spin-orbit coupling is developed and applied for the band structure and spin polarization calculation, as well as for the linear response analysis for charge current and induced spin caused by dc field and by electromagnetic radiation. It is found that the large spin-orbit coupling in this system may allow resolving the spin-dependent properties even at room temperature and at realistic collision rate. The geometry of the atomic lattice combined with spin-orbit coupling leads to an anisotropic response both for current and spin components related to the orientation of the external field. The in-plane dc electric field produces only the in-plane components of spin in the sample while both the in-plane and out-of-plane spin components can be excited by normally propagating electromagnetic wave with different polarizations.Comment: 10 pages, 9 figure

Multiferroic Coupling of Ferromagnetic and Ferroelectric Particles through Elastic Polymers

Multiferroics are materials that electrically polarize when subjected to a magnetic field and magnetize under the action of an electric field. In composites, the multiferroic effect is achieved by mixing of ferromagnetic (FM) and ferroelectric (FE) particles. The FM particles are prone to magnetostriction (field-induced deformation), whereas the FE particles display piezoelectricity (electrically polarize under mechanical stress). In solid composites, where the FM and FE grains are in tight contact, the combination of these effects directly leads to multiferroic behavior. In the present work, we considered the FM/FE composites with soft polymer bases, where the particles of alternative kinds are remote from one another. In these systems, the multiferroic coupling is different and more complicated in comparison with the solid ones as it is essentially mediated by an electromagnetically neutral matrix. When either of the fields, magnetic or electric, acts on the ‘akin’ particles (FM or FE) it causes their displacement and by that perturbs the particle elastic environments. The induced mechanical stresses spread over the matrix and inevitably affect the particles of an alternative kind. Therefore, magnetization causes an electric response (due to the piezoeffect in FE) whereas electric polarization might entail a magnetic response (due to the magnetostriction effect in FM). A numerical model accounting for the multiferroic behavior of a polymer composite of the above-described type is proposed and confirmed experimentally on a polymer-based dispersion of iron and lead zirconate micron-size particles. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The reported study was funded by the Russian Scientific Foundation according to research project No. 21-72-30032 (experimental investigation and analysis); authors Makarova L.A. and Isaev D.A. acknowledge the President of the Russian Federation Grant Number MK-716.2020.2 (simulation results). Authors Isaenko M.B. and Perov N.S. acknowledge partial support from Lomonosov Moscow State University Program of Development

EFFECT OF MECHANICAL DEFORMATION ON THE MAGNETIC CHARACTERISTICS OF FERROMAGNETIC OBJECTS MADE OF Fe-Ni ALLOYS

It is shown that cold plastic deformation of a number of iron-nickel alloys leads to a de-crease in the proportion of irreversible processes of magnetization reversal in their curves of return from the coercive force. An explanation of the experimental results is given on the basis of the model.Работа выполнена в рамках государственного задания МИНОБРНАУКИ России (тема «Диагностика», № АААА-А18-118020690196-3)

Масс-спектрометрия металлопорфиринов. 1. Масс-спектры октаэтилпорфиринатов меди, никеля и кобальта

Mass spectra of octaethylporphyrines of cobalt, nickel, copper with electron ionization were obtained. Molecular ions with isotope peaks and the peaks formed by separation hydrogen atoms from porhyrins core have maximum intensity. Appearance energies of some ions from OEP copper and its ionization energy have been determined. Electron ionization mass spectra at temperature up to 4000C and mass spectra at energies of ionizing electrons from 70 to 20 eV have been obtained for OEP copper. Ionization energy of OEP copper is 6.8±0.2 eV. It was concluded that OEP of copper, nickel, and cobalt in the gas phase are stable at least until 3000C.Масс-спектры октаэтилпорфиринатов (ОЭП) меди, никеля, кобальта получены при ионизации электронами. Наибольшую интенсивность имеют молекулярные ионы с изотопными пиками и пиками, образующиеся при отрыве атомов водорода от порфиринового остова. Определены энергии появления некоторых ионов из ОЭП меди и его энергия ионизации. Для ОЭП меди получены масс-спектры электронной ионизации при температуре вплоть до 4000С, а также масс-спектры при энергиях ионизирующих электронов от 70 до 20 эВ. Энергия ионизации ОЭП меди составляет 6.8±0.2 эВ. Сделан вывод, что ОЭП меди, никеля и кобальта в газовой фазе устойчивы, по крайней мере, до 4000С

Применение квантовых электронных устройств в периоперационном периоде у больных при ампутациях нижних конечностей

The authors present their experience in applying quantum electronic devices in patients undergoing lower limb amputations.Object. To develop a technique for potentiating the traditional multimodal anesthesia by optoelectronic devices with wavelength 650 nm (red range) and 470 nm (blue range) (manufactured in Russia) in amputation of lower extremities.Material and methods. Multimodal anesthesia with quantum electronic devices was performed in 48 patients (11 women and 37 men) aged 68–89 and having comorbidities. In the main group, for contact LED irradiation portable semiconductor LED device AFS к-630/670 emitting in red range with wavelength 650 ± 20 nm and portable AFS device emitting in blue range with wavelength 470 ± 10 nm and power 30 mW at the end of surgery were used. The above mentioned devices were made in the form of bracelets for non-invasive and non-contact application in the multimodal anesthesia during amputations of lower extremities. In the comparison group, multimodal anesthesia was not potentiated by contact LED irradiation.Results. The discussed Russian bracelets emitting in red and blue bands of the spectrum during amputation of lower extremities promoted the decrease of narcotic dosage (Fentanyl) during general multimodal anesthesia. In the main group, cardiac index increased at the end of surgery, and the total peripheral vascular resistance decreased if to compare to baseline values. In the comparison group, cardiac index increased somewhat less if to compare to baseline values, and the total peripheral vascular resistance decreased somewhat less if to compare to baseline values.Conclusion. The discussed bracelets emitting in red range (650 nm) which were applied during surgical interventions for the amputation of lower extremities and bracelets emitting in blue range (470 nm) which were applied at the end of surgery reduce the dose of narcotic preparations (Fentanyl) as well as stabilize hemodynamic parameters during surgery. Besides, in the immediate postoperative period, patients who survived amputation of lower extremities and in who the abovementioned bracelets were used do not require additional narcotic painkillers after amputation.В статье представлены результаты использования квантовых электронных устройств у пациентов при ампутациях нижних конечностей.Цель исследования – разработка методики потенцирования оптоэлектронными устройствами традиционной мультимодальной анестезии в области красного 650 нм и синего 470 нм диапазонов действия при ампутациях нижних конечностей.Материалы и методы исследования. Мультимодальная анестезия с применением квантовых электронных устройств была проведена у 48 пациентов (11 женщин и 37 мужчин) в возрасте от 68 до 89 лет с сопутствующими заболеваниями. Контактное светодиодное воздействие осуществляли в основной группе портативным полупроводниковым светодиодным аппаратом АФС к-630/670 в красном диапазоне действия с длиной волны 650 ± 20 нм и портативным аппаратом АФС в синем диапазоне действия с длиной волны 470 ± 10 нм мощностью 30 мВт в конце оперативного вмешательства. Устройства выполнены в виде браслетов на руку с целью неинвазивного бесконтактного применения, они использовались во время мультимодальной анестезии при ампутациях нижних конечностей. В группе сравнения мультимодальная анестезия не потенцировалась контактным светодиодным воздействием.Результаты исследования. Использование российских браслетов в красном и синем диапазонах действия во время проведения ампутаций нижних конечностей способствовало снижению дозы наркотических средств (фентанила) во время общей мультимодальной анестезии. В основной группе показатель сердечного индекса увеличивался в конце оперативного вмешательства, общее периферическое сосудистое сопротивление уменьшалось по сравнению с исходными значениями. В группе сравнения сердечный индекс увеличивался несколько меньше по сравнению с исходными данными, а общее периферическое сосудистое сопротивление также уменьшалось по сравнению с исходными данными.Заключение. Использование квантовых электронных устройств во время проведения оперативных вмешательств при ампутациях нижних конечностей позволяет снизить дозу наркотического препарата (фентанила) и стабилизировать гемодинамические показатели во время оперативного вмешательства. Кроме того, в ближайшем послеоперационном периоде не требуется дополнительное введение наркотических обезболивающих средств у пациентов с ампутациями нижних конечностей

Resonance Variations of the Microwave Refractive Index in YIG Plates

Abstract: The influence of microwave resonance phenomena on complex refractive index in YIG plates has been theoretically and experimentally studied in the frequency range 26–38 GHz. It has been shown that a change in the magnetic field causes severe resonance-type changes in transmission and reflection factors. These changes are due both to effective interaction between millimeter electromagnetic waves and YIG plates (specifically, under ferromagnetic resonance conditions) and to the fulfillment of geometrical resonance conditions (when an integer number of half-waves or an integer odd number of quarter-waves are accommodated on the thickness of the plate). An algorithm to calculate complex refractive index with regard to the tensor-type magnetic permeability of YIG is suggested. The field and frequency dependences of complex refractive index have been analyzed. Geometrical resonance fields have been compared with extrema in the field dependences of the transmission and reflection factor moduli. © 2019, Pleiades Publishing, Ltd.Russian Science Foundation, RSF: 17-12-01002