1,080 research outputs found

    Magnonic Charge Pumping via Spin-Orbit Coupling

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    The interplay between spin, charge, and orbital degrees of freedom has led to the development of spintronic devices like spin-torque oscillators, spin-logic devices, and spin-transfer torque magnetic random-access memories. In this development spin pumping, the process where pure spin-currents are generated from magnetisation precession, has proved to be a powerful method for probing spin physics and magnetisation dynamics. The effect originates from direct conversion of low energy quantised spin-waves in the magnet, known as magnons, into a flow of spins from the precessing magnet to adjacent normal metal leads. The spin-pumping phenomenon represents a convenient way to electrically detect magnetisation dynamics, however, precessing magnets have been limited so far to pump pure spin currents, which require a secondary spin-charge conversion element such as heavy metals with large spin Hall angle or multi-layer layouts to be detectable. Here, we report the experimental observation of charge pumping in which a precessing ferromagnet pumps a charge current, demonstrating direct conversion of magnons into high-frequency currents via the relativistic spin-orbit interaction. The generated electric current, differently from spin currents generated by spin-pumping, can be directly detected without the need of any additional spin to charge conversion mechanism and amplitude and phase information about the relativistic current-driven magnetisation dynamics. The charge-pumping phenomenon is generic and gives a deeper understanding of the recently observed spin-orbit torques, of which it is the reciprocal effect and which currently attract interest for their potential in manipulating magnetic information. Furthermore, charge pumping provides a novel link between magnetism and electricity and may find application in sourcing alternating electric currents.Comment: 3 figure

    The Associations of Experiencing the COVID-19 Pandemic With Religiosity and Spirituality:A Cross-Sectional Study in Czech Adults

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    Objectives: We investigated the associations between religiosity/spirituality and respondents' changes in their relationships, feelings, thinking, and behaviour during the first wave of the COVID-19 pandemic in the Czech Republic.Methods: A sample of Czech adults (n = 1,434; 48.3 +/- 16.4 years; 49.65% women) participated in the online survey. We measured spirituality, religiosity, self-reported changes in relationships, disrupted feelings, and changes in behaviour during the pandemic.Results: Spiritual respondents were more likely to report increased physical activity, sex, reading and self-education, with odds ratios (ORs) ranging from 1.26 (95% confidence interval 1.09-1.46) to 1.56 (1.31-1.86). The combination of spirituality and religiosity led to an increase in the range of ORs to 1.57-2.69. Spiritual and religious participants were less likely to feel the decrease of hope by 70%, while mere spirituality significantly reduced the decrease of hope by only 30%. Religiosity itself led to a lower risk of reporting a disrupted day structure with an OR = 0.74 (0.58-0.95).Conclusion: Religiosity and spirituality separately help people during a pandemic in some areas. Especially their combination has a more positive impact on relationships, feelings, and behaviour

    Nanostructures Defined by The Local Oxidation of Ferromagnetic GaMnAs Layer

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    The results of Local Anodic Oxidation (LAO) on the thin GaMnAs layers are reported. The ferromagnetic GaMnAs layers were prepared by low temperature MBE growth in a Veeco Mod Gen II machine. The LAO process was performed with the AFM microscope Smena NT-MDT placed in the sealed box with the controlled humidity in the range 45-80%. The oxide was grown in the semi-contact mode of the AFM. Sample was positively biased with respect to the AFM tip with the bias from 6 to 24 V. The conductive diamond coated AFM tips with the radius 30 nm were utilized for the oxidation. The tip speed during the oxidation was changed from 400 nm/s to 1.5 μm/s. The tip force was also changed during the oxidation. The height of oxide nanolines increases with applied voltage from 3 to 18 nm. The width of these lines was approximately 100 nm at half of the maximum

    Guidelines for Soil Description and Classification Central and Eastern European Students’ Version.

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    Soil investigation may be carried out on various levels of knowledge, research capacity and proficiency. Scientists commonly apply advanced methodology for soil resources inventory, including the professional terminology for landscape and soil description, data acquisition and processing, soil classification and mapping, soil and land evaluation. By default, an internationally accepted system should be recommended. An implementation of such methodology is also recommended in more advanced courses of soil science studies on bachelor and master study levels. However, the long-term teaching experience reveals difficulties connected mainly with complicated terminology and excessive number of characteristics obligatory to know, and justifies some simplification of the language, rules and structure at the introductory stage of teaching. This was the base and rationale for the preparation of simplified Guidelines for Soil Description and Classification: Central and Eastern European Students’ Version. This book is divided into three parts. The first one – Site and soil description - follows the layout and content of professional edition of Guidelines for Soil Description, 4th ed., published by FAO (2006), simplified for educational purposes. The order of description has been modified to correspond to the layout of an original Soil description sheet. The second part - Soil classification - is a simplified WRB classification (based on a 2014/2015 edition) limited to reference soil groups known from Central Europe. The third part is an Illustrated explanatory guide that includes: i) examples of typical soil profiles for all Central European Reference Soil Groups; ii) morphological features important for soil description and identification in the field; iii) soil- landscape relationships. The photos have been enriched with graphical tips helpful at the recognizing of important soil features. The textbook was developed in the framework of EU Erasmus+ FACES project (Freely Accessible Central European Soil) aiming to facilitate the knowledge and implementation of an international rules of soil characterization adopted by the FAO. It will be used to unify the presentation of soil data collected in the partner countries. The interpretation of soil data fully based on the international soil classification WRB (World Reference Base for Soil Resources 2015) as WRB was endorsed by the International Union of Soil Sciences (IUSS) and accepted by the European Commission as an official system for the European Union. Therefore, this guideline might be a starting point for preparation of basic teaching materials to spread the knowledge on an internationally recommended rules and terminology for soil description and classification. However, this guideline is designed as teaching tool for students in Central and Eastern European countries and therefore it may not be applicable worldwide. Moreover, it is suited for the “first step” training, and it is not substituting any professional original classification. Authors of this guidebook assume that the users are familiar with the basic knowledge in soil science. Therefore, the guidelines do not contain explanations related to basic soil forming factors, soil forming processes and basic physico-chemical features

    Current polarity-dependent manipulation of antiferromagnetic domains

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    Antiferromagnets have several favourable properties as active elements in spintronic devices, including ultra-fast dynamics, zero stray fields and insensitivity to external magnetic fields. Tetragonal CuMnAs is a testbed system in which the antiferromagnetic order parameter can be switched reversibly at ambient conditions using electrical currents. In previous experiments, orthogonal in-plane current pulses were used to induce 90° rotations of antiferromagnetic domains and demonstrate the operation of all-electrical memory bits in a multi-terminal geometry. Here, we demonstrate that antiferromagnetic domain walls can be manipulated to realize stable and reproducible domain changes using only two electrical contacts. This is achieved by using the polarity of the current to switch the sign of the current-induced effective field acting on the antiferromagnetic sublattices. The resulting reversible domain and domain wall reconfigurations are imaged using X-ray magnetic linear dichroism microscopy, and can also be detected electrically. Switching by domain-wall motion can occur at much lower current densities than those needed for coherent domain switching

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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