82 research outputs found
Spin-Orbitronics a Novel Trend in Spin Oriented Electronics
Introduction. The advent of spin oriented electronics, or spintronics, in the late 1980ies has not only revolutionised the very idea of contemporary electronics but has also brought about a major technological breakthrough in the field of information storage and processing. Further progress is associated with the rapidly emerging field of spinorbitronics seeking to put to maximum use the SOC (Spin-Orbit Coupling) related phenomena.Aim. The purpose of this review paper is to outline the major trends in the dynamically developing field of spinorbitronics in the context of evolution of the mainstream spintronics. SOC related effects open up the possibility of creation of a new generation of energy saving devices, a key challenge in electronics in general.Materials and methods. A special effort has been undertaken to make the article appealing to the general reader, especially to specialists in the field of radioelectronics and data processing. To this end, in the description of the complex physics underlying magnetic interactions preference is given to simple term "naive" interpretations.Results. Apart from the analysis of the fundamental features peculiar to the interfaces between ultrathin films of ferromagnetic and heavy metals and related to strong SOC, we discuss specific configurations especially promising for application-oriented research. Among others, these include spin torque microwave (1...50 GHz) oscillators, fast domain walls in racetrack memory and especially magnetic skyrmions.Conclusion. Publication of this paper will facilitate creative interaction between the fundamental and applied research, thus contributing to the development of novel high-performance spintronic devices.Introduction. The advent of spin oriented electronics, or spintronics, in the late 1980ies has not only revolutionised the very idea of contemporary electronics but has also brought about a major technological breakthrough in the field of information storage and processing. Further progress is associated with the rapidly emerging field of spinorbitronics seeking to put to maximum use the SOC (Spin-Orbit Coupling) related phenomena.Aim. The purpose of this review paper is to outline the major trends in the dynamically developing field of spinorbitronics in the context of evolution of the mainstream spintronics. SOC related effects open up the possibility of creation of a new generation of energy saving devices, a key challenge in electronics in general.Materials and methods. A special effort has been undertaken to make the article appealing to the general reader, especially to specialists in the field of radioelectronics and data processing. To this end, in the description of the complex physics underlying magnetic interactions preference is given to simple term "naive" interpretations.Results. Apart from the analysis of the fundamental features peculiar to the interfaces between ultrathin films of ferromagnetic and heavy metals and related to strong SOC, we discuss specific configurations especially promising for application-oriented research. Among others, these include spin torque microwave (1...50 GHz) oscillators, fast domain walls in racetrack memory and especially magnetic skyrmions.Conclusion. Publication of this paper will facilitate creative interaction between the fundamental and applied research, thus contributing to the development of novel high-performance spintronic devices
Probing the Dzyaloshinskii-Moriya interaction in CoFeB ultrathin films using domain wall creep and Brillouin light spectroscopy
We have characterized the strength of the interfacial Dyzaloshinskii-Moriya
interaction (DMI) in ultrathin perpendicularly magnetized CoFeB/MgO films,
grown on different underlayers of W, TaN, and Hf, using two experimental
methods. First, we determined the effective DMI field from measurements of
field-driven domain wall motion in the creep regime, where applied in-plane
magnetic fields induce an anisotropy in the wall propagation that is correlated
with the DMI strength. Second, Brillouin light spectroscopy was employed to
quantify the frequency non-reciprocity of spin waves in the CoFeB layers, which
yielded an independent measurement of the DMI. By combining these results, we
show that DMI estimates from the different techniques only yield qualitative
agreement, which suggests that open questions remain on the underlying models
used to interpret these results.Comment: 8 page
Magnetization pinning in conducting films demonstrated using broadband ferromagnetic resonance
The broadband microstrip ferromagnetic resonance technique has been applied
for detection and characterization of a magnetic inhomogeneity in a film
sample. In the case of a 100nm thick Permalloy film an additional magnetically
depleted top sub-layer, practically unidentifiable by the conventional
ferromagnetic resonance setup, has been detected and characterized. These
results have been confirmed by Brillouin light scattering spectroscopy
revealing the fact that the optical properties of the additional sub-layer do
not differ much from those of the bulk of the film. Subsequent characterization
of a large number of other presumably single-layer films with thicknesses in
the range 30-100nm using the same ferromagnetic resonance technique also
revealed the same effect
Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires
We study optical properties of arrays of ultrathin nanowires by means of the
Brillouin scattering of light on magnons. We employ the Stokes/anti-Stokes
scattering asymmetry to probe the circular polarization of a local electric
field induced inside nanowires by linearly polarized light waves. We observe
the anomalous polarization conversion of the opposite sign than that in a bulk
medium or thick nanowires with a great enhancement of the degree of circular
polarization attributed to an unconventional refraction in the nanowire medium.Comment: 5 pages, 4 figure
Combinations of proinflammatory cytokine genes and their interactions in Russian tuberculosis patients in the Chelyabinsk Region
Tuberculosis is a widespread infectious disease caused by M. tuberculosis, which is one of the leading causes of death in the world. According to numerous literature data, this is a genetically determined disease, and genetical polymorphism is a mechanism that leads to progression from infection to clinical manifestation. Susceptibility to infection correlates with different genes at several loci, and each individual gene plays a unique role. It is known, that the analysis of individual polymorphic variants of genes does not provide a sufficiently complete picture of the mechanisms of formation of a predisposition to multifactorial pathologies, such as tuberculosis, since their development is based on complex intergenic and gene-environmental interactions, which must be taken into account when predicting the risk of developing active forms of the disease and its severity. The concept of the functioning of cytokines as biomarkers of tuberculosis suggests that their products and interactions play an important role in the immunopathogenesis of the disease, because they form a cytokine chain with unique functions, where the removal of any link in the chain disrupts the entire mechanism of the immuno-inflammatory process. IL-6, together with TNFα and IL-1β, initiate early pro-inflammatory reactions in tuberculosis, stimulating local and systemic inflammatory reactions under participation of all common pro-inflammatory mechanisms with further transition to activation of acquired immunity. Earlier, we carried out a set of studies to evaluate the association of alleles and genotypes of these cytokine genes with a predisposition/resistance to pulmonary tuberculosis in Russians of the Chelyabinsk region. These studies have resulted into assessment of certain distribution patterns of IL-1β, TNFα, IL-6 alleles and their genotypes in pulmonary tuberculosis and its various clinical forms. The following methods were used: isolation of DNA samples from whole blood, genotyping of the studied gene polymorphisms using PCR and RFLP techniques. In this study, we analyzed the intergenic interactions of the genes for the pro-inflammatory cytokines IL-1β, TNFα, IL-6 using the method of reducing multifactor dimension in patients with pulmonary tuberculosis. The program designs optimal models of combinations for the studied genes and their interactions in tuberculosis patients. As a result of this study, a three-locus model IL-6 (-174)*С – IL-1β (+3953)*Т – IL-1β (+3953)*С was established, which was characterized by 100% reproducibility and prediction accuracy of 72%. Among the analyzed polymorphisms, the IL-6 (-174)*C polymorphism possessed the highest predictive potential with 15.27%
Immunogenetic profile of MIC (A, B) HLA loci linked to MHC antigenic complex in Russians of the Chelyabinsk Region
The MIC genes are located on chromosome 6 in the class I major histocompatibility complex (MHC) region and encode a membrane-bound stress-inducible protein that acts as a ligand to stimulate the NKG2D activating receptor expressed on the surface of the most natural killer cells (NK). Currently, 7 MIC loci are known, of which only MICA and MICB encode proteins and show a significant allelic polymorphism. The MIC gene polymorphism and their location in the HLA region suggests presence of some ethnic and populational differences for the gene frequencies, linkage disequilibrium of distinct loci, and distribution of HLA-MIC haplotypes, thus making it possible to get information on genetic relationship of human populations. The aim of our study was to assess immunogenetic profile of Russian population in Chelyabinsk Region based on the non-classical HLA loci, i.e., MICA and MICB, in the context of worldwide population data. Methods of the study included immunogenetic typing of 100 donors identifying themselves as Russians, taken from the Registry of Stem Cell Donors at the Chelyabinsk Regional Blood Transfusion Station. The 2 loci (MICA and MICB) were typed at basic resolution, using PCR technique with sequence-specific primers (SSP-PCR). Gene frequencies (GF) were calculated using programs for immunogenetic research (Arlequin 3.5).Among Russian population from Chelyabinsk Region, the following characteristics of the MICA gene distributions were found: MICA *008, *002, *010, *009, frequency of > 7%; average frequencies, for MICA *004, *007, *018, *017; whereas MICA *027, *011, *006, *009:02, *049, *012, *016 was registered at a frequency of < 3.5%. MICB gene profile was as follows: MICB *005:02, *004, *002, *008 at a frequency of > 6%; at a frequency of 4% MICB *003, *005:03; MICB *005:01, * 005:04, * 009N, MICB *013, *014 at a frequency of0.5%. As based on calculated genetic distances (according to Ney) for the MICA locus, the dendrogram and scatter plot were designed by means of multidimensional scaling (MDS) method, presenting location of 30 world populations, including data on Russians in Chelyabinsk Region. The smallest genetic distances between the population of Russians from Chelyabinsk Region and other world populations were found between the population of Slovenia, as well as the USA population of European origin. As based on scatterplot obtained by the MDS approach for MICA gene frequencies, using the data of cluster analysis, we have found that the population of Russians from Chelyabinsk Region belongs to a cluster of typical European populations.The obtained patterns could be used for practical purposes to create a registry of stem cell donors in Russia. In addition, the data may be used as a control group for further research in the area of HLA-disease association, and could be also demanded by the specialists in population ethnogenesis
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