Domain wall effects in ferromagnet-superconductor structures

We investigate how domain structure of the ferromagnet in superconductor-ferromagnet heterostructures may change their transport properties. We calculate the distribution of current in the superconductor induced by magnetic field of Bloch domain walls, find the ``lower critical'' magnetization of the ferromagnet that provides vortices in the superconductor

Hierarchy of critical temperatures in four-layered ferromagnet/ superconductor nanostructures and control devices

The four-layered F/S/F′/S′ nanostructure consisting of rather dirty superconducting (S) and ferromagnetic (F) metals is studied within the theory of the proximity effect taking detailed account of the boundary conditions. The F/S structures with four F and S layers are shown to have considerably richer physics than the F/S/F trilayer (due to the interplay between the 0 and π phase superconductivity and the 0 and π phase magnetism) and even the F/S superlattices. The extra π phase superconducting states obtained for the four-layered F/S/F′/S′ system are found to be different from the known "superlattice" states. The dependence of the critical temperatures versus the F layer thicknesses is investigated. An optimal set of parameters is determined, for which the difference between the critical temperatures for different states becomes significant, and the corresponding phase diagrams are plotted. It is proven that this system can have different critical temperatures for different S and S′ layers. A conceptual scheme of a control device with superconducting and magnetic recording channels that can be controlled separately using a weak external magnetic field is proposed on the basis of the F/S/F′/S′ nanostructure. The devices with four, five, six, and seven different states are explored. © 2006 The American Physical Society

Decoupled superconductivity in the four- and five-layered ferromagnet-superconductor nanostructures and control devices

The ferromagnet/superconductor (F/S) tetra- and pentalayer consisting of rather dirty metals are considered with regard for the boundary conditions. The dependences of critical temperatures Tc versus the thicknesses of the F layers are investigated. The clearest manifestation of decoupled superconductivity for the F′/S′/F″/S″ tetralayer is the rise of a hierarchy of transition temperature Tc, and different S′ and S″ layers can have different critical temperatures. The same is valid for nonsymmetrical case of the F′/S′/F″/S″/ F‴ pentalayer. The complicated phase diagram of the tetralayer is discussed. The inverse action of superconductivity on magnetism leads to preferable mutual antiferromagnetic orientation of magnetizations of the F′ and F″ layers, if the inner S′ layer is in the superconducting state. Conceptual scheme of the new nanoelectronics control device, that has up to seven different states and combine in one sample the advantages of two different recording channels, is proposed. © 2005 Elsevier B.V. All rights reserved

Critical temperature of superconductor/ferromagnet bilayers

Superconductor/ferromagnet bilayers are known to exhibit nontrivial dependence of the critical temperature T_c on the thickness d_f of the ferromagnetic layer. We develop a general method for investigation of T_c as a function of the bilayer's parameters. It is shown that interference of quasiparticles makes T_c(d_f) a nonmonotonic function. The results are in good agreement with experiment. Our method also applies to multilayered structures.Comment: 4 pages, 2 EPS figures; the style file jetpl.cls is included. Version 2: typos correcte

Experimental Simulation of the Radionuclide Behaviour in the Process of Creating Additional Safety Barriers in Solid Radioactive Waste Repositories Containing Irradiated Graphite

Results of the experimental modeling of radionuclide behavior when creating additional safety barriers in solid radioactive waste repositories are presented. The experiments were run on the repository mockup containing solid radioactive waste fragments including irradiated graphite. The repository mockup layout is given; the processes with radionuclides that occur during the barrier creation with a clayey solution and during the following barrier operation are investigated. The results obtained confirm high anti-migration and anti-filtration properties of clay used for the barrier creation even under the long-term excessive water saturation of rocks confining the repository

Stress-induced aggression in heterozygous TPH2 mutant mice is associated with alterations in serotonin turnover and expression of 5-HT6 and AMPA subunit 2A receptors

Background: The contribution of gene-environment interactions that lead to excessive aggression is poorly understood. Environmental stressors and mutations of the gene encoding tryptophan hydroxylase-2 (TPH2) are known to influence aggression. For example, TPH2 null mutant mice (Tph2−/−) are naturally highly aggressive, while heterozygous mice (Tph2+/−) lack a behavioral phenotype and are considered endophenotypically normal. Here we sought to discover whether an environmental stressor would affect the phenotype of the genetically ‘susceptible’ heterozygous mice (Tph2+/−). Methods: Tph2+/− male mice or Tph2+/+ controls were subjected to a five-day long rat exposure stress paradigm. Brain serotonin metabolism and the expression of selected genes encoding serotonin receptors, AMPA receptors, and stress markers were studied. Results: Stressed Tph2+/− mice displayed increased levels of aggression and social dominance, whereas Tph2+/+ animals became less aggressive and less dominant. Brain tissue concentrations of serotonin, its precursor hydroxytryptophan and its metabolite 5-hydroxyindoleacetic acid were significantly altered in all groups in the prefrontal cortex, striatum, amygdala, hippocampus and dorsal raphe after stress. Compared to non-stressed animals, the concentration of 5-hydroxytryptophan was elevated in the amygdala though decreased in the other brain structures. The overexpression of the AMPA receptor subunit, GluA2, and downregulation of 5-HT6 receptor, as well as overexpression of c-fos and glycogen-synthase-kinase-3β (GSK3-β), were found in most structures of the stressed Tph2+/− mice. Limitations: Rescue experiments would help to verify causal relationships of reported changes. Conclusions: The interaction of a partial TPH2 gene deficit with stress results in pathological aggression and molecular changes, and suggests that the presence of genetic susceptibility can augment aggression in seemingly resistant phenotypes. © 2020 The Authors602805Seventh Framework Programme, FP7Deutsche Forschungsgemeinschaft, DFG: CRC TRR 58 A1/A5Horizon 2020 Framework Programme, H2020: 728018Russian Foundation for Basic Research, RFBR: 15-04-03602Deutsche Forschungsgemeinschaft, DFGRussian Foundation for Basic Research, RFBRThe authors’ work reported here was supported Deutsche Forschungsgemeinschaft (DFG: CRC TRR 58 A1/A5), the European Union's Seventh Framework Programme (FP7/2007–2013) under Grant No. 602805 (Aggressotype) and the Horizon 2020 Research and Innovation Programme under Grant No. 728018 (Eat2beNICE) (to KPL and TS), the “5-100” Russian Academic Excellence Project (to KPL and TS) and the Russian Foundation of Basic Research (RFBR Grant No. 15-04-03602 to TS). We appreciate the valuable technical help of Dr. Joao Costa-Nunes and Dolores Bonopartos with this project

МОРФОЛОГИЧЕСКИЕ ИЗМЕНЕНИЯ МОЛОЧНОЙ ЖЕЛЕЗЫ И ЯИЧНИКОВ У МЫШЕЙ С ЭКСПЕРИМЕНТАЛЬНО ИЗМЕНЕННЫМ ТИРЕОИДНЫМ СТАТУСОМ

The frequency of breast tumors has been studied in inbreed C3H-A mice with affected thyroid status. It has been shown that frequency of breast tumors was significantly higher in the animals with hyperthyroid condition versus the hypothyroid group (рИсследовали частоту возникновения рака молочной железы у инбредных мышей линии С3Н-А с измененным тиреоидным статусом. Выявлено, что частота возникновения рака молочной железы была достоверно выше у животных с длительно протекающим гипертиреозом по сравнению с гипотиреоидной группой (

Proximity effects in superconductor-ferromagnet heterostructures

The very special characteristic of the proximity effect in superconductor-ferromagnet systems is the damped oscillatory behavior of the Cooper pair wave function in a ferromagnet. In some sense, this is analogous to the inhomogeneous superconductivity, predicted long time ago by Larkin and Ovchinnikov (1964), and Fulde and Ferrell (1964), and constantly searched since that. After the qualitative analysis of the peculiarities of the proximity effect in the presence of the exchange field, the author provides a unified description of the properties of the superconductor-ferromagnet heterostructures. Special attention is paid to the striking non-monotonous dependance of the critical temperature of the multilayers and bilayers on the ferromagnetic layer thickness and conditions of the realization of the "Pi"- Josephson junctions. The recent progress in the preparation of the high quality hybrid systems permitted to observe on experiments many interesting effects, which are also discussed in the article. Finally, the author analyzes the phenomenon of the domain-wall superconductivity and the influence of superconductivity on the magnetic structure in superconductor-ferromagnet bilayers.Comment: Submitted to Reviews of Modern Physic

Adjustment of superconductivity and ferromagnetism in few-layered ferromagnet-superconductor nanostructures

The phase diagrams of the few-layered nanosystems consisting of dirty superconducting (S) and ferromagnetic (F) metals are investigated within the framework of the modern theory of the proximity effect taking into account the boundary conditions. The F/S tetralayer and pentalayer are shown to have considerably richer physics than the F/S bi- and trilayer (due to the interplay between the 0 and π phase superconductivity and the 0 and π phase magnetism and nonequivalence of layers) and even the F/S superlattices. It is proven that these systems can have different critical temperatures and fields for different S layers. This predicted decoupled superconductivity is found to manifest itself in its most striking way for F/S tetralayer. It is shown that F/S/F/S tetralayer is the most perspective candidate for use in superconducting spin nanoelectronics