6,050 research outputs found
Electrical detectability of magnon-mediated spin current shot noise
A magnonic spin current crossing a ferromagnet-metal interface is accompanied
by spin current shot noise arising from the discrete quanta of spin carried by
magnons. In thin films, e.g., the spin of so-called squeezed magnons have been
shown to deviate from the common value , with corresponding changes in
the spin noise. In experiments, spin currents are typically converted to charge
currents via the inverse spin Hall effect. We here analyze the magnitude of the
spin current shot noise in the charge channel for a typical electrically
detected spin pumping experiment, and find that the voltage noise originating
from the spin current shot noise is much smaller than the inevitable
Johnson-Nyquist noise. Furthermore, we find that due to the local nature of the
spin-charge conversion, the ratio of spin current shot noise and
Johnson-Nyquist noise cannot be systematically enhanced by tuning the sample
geometry, in contrast to the linear increase in dc spin pumping voltage with
sample length. Instead, the ratio depends sensitively on material-specific
transport properties. Our analysis thus provides guidance for the experimental
detection of squeezed magnons through spin pumping shot noise.Comment: Revised manuscript title, added paragraph of interpretation of the
shot noise enhancement with temperature, added brief discussion of the low
temperature limit, references adde
Control of nonlocal magnon spin transport via magnon drift currents
Spin transport via magnon diffusion in magnetic insulators is important for a
broad range of spin-based phenomena and devices. However, the absence of the
magnon equivalent of an electric force is a bottleneck. In this work, we
demonstrate the controlled generation of magnon drift currents in yttrium iron
garnet/platinum heterostructures. By performing electrical injection and
detection of incoherent magnons, we find magnon drift currents that stem from
the interfacial Dzyaloshinskii-Moriya interaction. We can further control the
magnon drift by the orientation of the magnetic field. The drift current
changes the magnon propagation length by up to 6 % relative to diffusion.
We generalize the magnonic spin transport theory to include a finite drift
velocity resulting from any inversion asymmetric interaction, and obtain
results consistent with our experiments.Comment: 6 pages, 3 figure
All Electrical Access to Topological Transport Features in MnPtSn Films
The presence of non-trivial magnetic topology can give rise to non-vanishing
scalar spin chirality and consequently a topological Hall or Nernst effect. In
turn, topological transport signals can serve as indicators for topological
spin structures. This is particularly important in thin films or nanopatterned
materials where the spin structure is not readily accessible. Conventionally,
the topological response is determined by combining magnetotransport data with
an independent magnetometry experiment. This approach is prone to introduce
measurement artifacts. In this study, we report the observation of large
topological Hall and Nernst effects in micropatterned thin films of
MnPtSn below the spin reorientation temperature K. The magnitude of the topological Hall effect
nm is close to the value reported in
bulk MnPtSn, and the topological Nernst effect nV K measured in the same microstructure has a similar magnitude as
reported for bulk MnGe ( nV K), the
only other material where a topological Nernst was reported. We use our data as
a model system to introduce a topological quantity, which allows to detect the
presence of topological transport effects without the need for independent
magnetometry data. Our approach thus enables the study of topological transport
also in nano-patterned materials without detrimental magnetization related
limitations.Comment: 8 pages, 3 figure
Lipids From Trypanosoma cruzi Amastigotes of RA and K98 Strains Generate a Pro-inflammatory Response via TLR2/6
Lipids from microorganisms are ligands of Toll like receptors (TLRs) and modulate the innate immune response. Herein, we analyze in vitro the effect of total lipid extracts from Trypanosoma cruzi amastigotes of RA and K98 strains (with polar biological behavior) on the induction of the inflammatory response and the involvement of TLRs in this process. We demonstrated that total lipid extracts from both strains induced lipid body formation, cyclooxygenase-2 expression and TNF-a and nitric oxide release in macrophages, as well as NF-ÎșB activation and IL-8 release in HEK cells specifically through a TLR2/6 dependent pathway. We also evaluated the inflammatory response induced by total lipid extracts obtained from lysed parasites that were overnight incubated to allow the action of parasite hydrolytic enzymes, such as Phospholipase A1, over endogenous phospholipids. After incubation, these total lipid extracts showed a significantly reduced pro-inflammatory response, which could be attributed to the changes in the content of known bioactive lipid molecules like lysophospholipids and fatty acids, here reported. Moreover, analyses of total fatty acids in each lipid extract were performed by gas chromatography-mass spectrometry. Our results indicate a relevant role of T. cruzi lipids in the induction of a pro-inflammatory response through the TLR2/6 pathway that could contribute to the modulation of the immune response and host survival.Fil: Bott, Emanuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; ArgentinaFil: Carneiro, Alan B.. Instituto Oswaldo Cruz; BrasilFil: Gimenez, Guadalupe. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; ArgentinaFil: LĂłpez, MarĂa Gabriela. Instituto Nacional de TecnologĂa Agropecuaria; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Lammel, Estela MarĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; ArgentinaFil: Atella, Georgia C.. Universidade Federal do Rio de Janeiro; BrasilFil: Bozza, Patricia T.. Instituto Oswaldo Cruz; BrasilFil: BelaunzarĂĄn, MarĂa Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂa y ParasitologĂa MĂ©dica; Argentin
Spin-Hall-Active Platinum Thin Films Grown Via Atomic Layer Deposition
We study the magnetoresistance of yttrium iron garnet/Pt heterostructures in
which the Pt layer was grown via atomic layer deposition (ALD).
Magnetotransport experiments in three orthogonal rotation planes reveal the
hallmark features of spin Hall magnetoresistance. We estimate the spin
transport parameters by comparing the magnitude of the magnetoresistance in
samples with different Pt thicknesses. We compare the spin Hall angle and the
spin diffusion length of the ALD Pt layers to the values reported for
high-quality sputter-deposited Pt films. The spin diffusion length of 1.5nm
agrees well with platinum thin films reported in the literature, whereas the
spin Hall magnetoresistance is
approximately a factor of 20 smaller compared to that of our sputter-deposited
films. Our results demonstrate that ALD allows fabricating spin-Hall-active Pt
films of suitable quality for use in spin transport structures. This work
provides the basis to establish conformal ALD coatings for arbitrary surface
geometries with spin-Hall-active metals and could lead to 3D spintronic devices
in the future.Comment: 11 pages, 3 figure
Rabies screen reveals GPe control of cocaine-triggered plasticity.
Identification of neural circuit changes that contribute to behavioural plasticity has routinely been conducted on candidate circuits that were preselected on the basis of previous results. Here we present an unbiased method for identifying experience-triggered circuit-level changes in neuronal ensembles in mice. Using rabies virus monosynaptic tracing, we mapped cocaine-induced global changes in inputs onto neurons in the ventral tegmental area. Cocaine increased rabies-labelled inputs from the globus pallidus externus (GPe), a basal ganglia nucleus not previously known to participate in behavioural plasticity triggered by drugs of abuse. We demonstrated that cocaine increased GPe neuron activity, which accounted for the increase in GPe labelling. Inhibition of GPe activity revealed that it contributes to two forms of cocaine-triggered behavioural plasticity, at least in part by disinhibiting dopamine neurons in the ventral tegmental area. These results suggest that rabies-based unbiased screening of changes in input populations can identify previously unappreciated circuit elements that critically support behavioural adaptations
Types and characteristics of urban and peri-urban green spaces having an impact on human mental health and wellbeing: a systematic review
Green spaces have been put forward as contributing to good mental health. In an urban context, space is a scarce resource while urbanisation and climate change are increasingly putting pressure on existing urban green space infrastructures and increasing morbidity caused by mental health disorders. Policy makers, designers, planners and other practitioners face the challenge of designing public open spaces as well as preserving and improving natural resources that are important for maintaining and optimizing human wellbeing. Knowing which types of blue and green spaces, with which characteristics, are most beneficial for mental health and wellbeing is critical.
EKLIPSE received a request from the Ministry in charge of the Environment of France (MTES) to review: âWhich types of urban and periâurban green and blue spaces, and which characteristics of such spaces, have a significant impact on human mental health and wellbeing?â. After a preliminary scoping, a decision was made to perform two systematic reviews (SR) assessing the specific types and characteristics of blue space (SR1) and green space (SR2) with respect to mental health and wellbeing. This report presents the systematic review for green space (SR2)
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