We have examined a dynamical spin injection in a CoFeB/Pt/CoFeB trilayered structure. Although the contribution of the spin pumping was eliminated by the symmetric spin injection from the upper and ...lower CoFeB layers, a clear voltage change due to the inverse spin Hall effect has been observed. We find that the observed signal can be quantitatively explained by considering the thermal spin injection due to the heating effect during ferromagnetic resonance (FMR). This innovative demonstration indicates the significant contribution of FMR heating in the dynamical spin injection.
A large spin accumulation due to the electrical spin injection has been observed in Permalloy-silver lateral spin-valve structures. The observed resistance change is the largest among the reported ...metallic lateral spin valves with Ohmic junctions. The spin-diffusion length deduced from the experimental results is also found to be the longest among the normal metals reported so far. All the results can be quantitatively explained by the common spin-diffusion model without any discrepancies unlike the results of Godfrey and Johnson.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract
In vortex-like spin arrangements, multiple spins can combine into emergent multipole moments. Such multipole moments have broken space-inversion and time-reversal symmetries, and can ...therefore exhibit linear magnetoelectric (ME) activity. Three types of such multipole moments are known: toroidal; monopole; and quadrupole moments. So far, however, the ME activity of these multipole moments has only been established experimentally for the toroidal moment. Here we propose a magnetic square cupola cluster, in which four corner-sharing square-coordinated metal-ligand fragments form a noncoplanar buckled structure, as a promising structural unit that carries an ME-active multipole moment. We substantiate this idea by observing clear magnetodielectric signals associated with an antiferroic ME-active magnetic quadrupole order in the real material Ba(TiO)Cu
4
(PO
4
)
4
. The present result serves as a useful guide for exploring and designing new ME-active materials based on vortex-like spin arrangements.
Materials that combine coupled electric and magnetic dipole order are termed 'magnetoelectric multiferroics'. In the past few years, a new class of such materials, 'induced-multiferroics', has been ...discovered, wherein non-collinear spiral magnetic order breaks inversion symmetry, thus inducing ferroelectricity. Spiral magnetic order often arises from the existence of competing magnetic interactions that reduce the ordering temperature of a more conventional collinear phase. Hence, spiral-phase-induced ferroelectricity tends to exist only at temperatures lower than approximately 40 K. Here, we propose that copper(II) oxides (containing Cu2+ ions) having large magnetic superexchange interactions can be good candidates for induced-multiferroics with high Curie temperature (T(C)). In fact, we demonstrate ferroelectricity with T(C)=230 K in cupric oxide, CuO (tenorite), which is known as a starting material for the synthesis of high-T(c) (critical temperature) superconductors. Our result provides an important contribution to the search for high-temperature magnetoelectric multiferroics.
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IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Recently, CuO has been proposed as a potential multiferroic material with high transition temperature. Competing models based on spin current and ionic displacements are invoked to explain ...ferroelectricity in CuO. The theoretical model based on ionic displacement predicted very small displacement (∼10−5 Å) along the b axis. Experimentally detecting displacements of such a small amplitude in a particular direction is extremely challenging. Through our detailed angle resolved polarized Raman spectroscopy study on single crystal of CuO, we have validated the theoretical study and provided direct evidence of displacement along the b axis. Our study provides important contribution in the high temperature multiferroic compounds and showed for the first time, the use of the polarized Raman scattering in detecting ionic displacements at the femtometer scale.
Materials that combine coupled electric and magnetic dipole order are termed 'magnetoelectric multiferroics'. In the past few years, a new class of such materials, 'induced-multiferroics', has been ...discovered, wherein non-collinear spiral magnetic order breaks inversion symmetry, thus inducing ferroelectricity. Spiral magnetic order often arises from the existence of competing magnetic interactions that reduce the ordering temperature of a more conventional collinear phase. Hence, spiral-phase-induced ferroelectricity tends to exist only at temperatures lower than ∼40 K. Here, we propose that copper(II) oxides (containing Cu2+ ions) having large magnetic superexchange interactions can be good candidates for induced-multiferroics with high Curie temperature (TC). In fact, we demonstrate ferroelectricity with TC=230 K in cupric oxide, CuO (tenorite), which is known as a starting material for the synthesis of high-Tc (critical temperature) superconductors. Our result provides an important contribution to the search for high-temperature magnetoelectric multiferroics.
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IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Objective
To examine the association between maternal alcohol consumption during pregnancy and the risk of preterm delivery.
Design
Prospective cohort study.
Setting
The Japan Environment and ...Children's Study (JECS).
Population
A total of 94 349 singleton pregnancies.
Methods
Participants completed questionnaires detailing alcohol consumption during the first trimester and during the second and third trimesters. Participants were divided into four categories according to alcohol consumption (non‐drinkers, consumers of 1–149 g, 150–299 g and ≥300 g ethanol/week). We examined the effect of alcohol consumption during different stages of pregnancy on the risk of preterm delivery. Odds ratios (OR) and 95% CI were calculated relative to non‐drinkers using logistic regression.
Main outcome measures
Medical record‐based preterm delivery.
Results
Alcohol consumption during the second and third trimesters, but not during the first trimester, was associated with increased risk of preterm delivery. Heavy alcohol consumption (≥300 g ethanol/week) during the second and third trimesters was associated with a four‐fold higher risk compared with non‐drinkers (multivariable OR 4.52; 95% CI 1.68–12.2). Light alcohol consumption (1–149 g ethanol/week) tended to be associated with lower risk of preterm delivery (multivariable OR 0.78; 95% CI 0.60–1.00).
Conclusions
Heavy alcohol consumption during the second and third trimesters was associated with increased risk of preterm delivery among pregnant women.
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Heavy drinking during pregnancy may increase the risk of preterm delivery.
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Heavy drinking during pregnancy may increase the risk of preterm delivery.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present the first comparison of Jupiter's auroral morphology with an extended, continuous, and complete set of near‐Jupiter interplanetary data, revealing the response of Jupiter's auroras to the ...interplanetary conditions. We show that for ∼1–3 days following compression region onset, the planet's main emission brightened. A duskside poleward region also brightened during compressions, as well as during shallow rarefaction conditions at the start of the program. The power emitted from the noon active region did not exhibit dependence on any interplanetary parameter, though the morphology typically differed between rarefactions and compressions. The auroras equatorward of the main emission brightened over ∼10 days following an interval of increased volcanic activity on Io. These results show that the dependence of Jupiter's magnetosphere and auroras on the interplanetary conditions are more diverse than previously thought.
Plain Language Summary
Jupiter's auroras (northern lights) are the brightest in the solar system, over a hundred times brighter than the Earth's. Auroras on Earth are driven by the solar wind, a million mile‐per‐hour stream of charged particles flowing away from the Sun, hitting the Earth's magnetic field, and stirring it around, but it is not known whether the solar wind causes any significant auroras on Jupiter. The main reason for this uncertainty is a lack of observations of the planet's auroras obtained while spacecraft have been near Jupiter and able to supply a full and continuous set of measurements of the solar wind and its accompanying magnetic field. In early mid‐2016 Juno approached Jupiter, providing such an interplanetary data set, and we obtained over a month's worth of observations of Jupiter's auroras using the Hubble Space Telescope. We saw several solar wind storms, each causing auroral fireworks on Jupiter. We captured the most powerful auroras observed by Hubble to date, brightened main oval emissions, and flashing high‐latitude patches of auroras during the solar wind storms. These results indicate that Jupiter's auroral response to the solar wind is more diverse than we previously have thought.
Key Points
We present the first comparison of Jupiter's auroras with an extended and complete set of near‐Jupiter interplanetary data
During compressions, the well‐defined sector of Jupiter's emission and the dusk poleward region brightened, the latter pulsating
The power emitted from the noon active region did not exhibit dependence on any interplanetary parameter, though the morphology changed
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The voltage change accompanying the magnetization reversal in a CoFeB/W bilayer system has been investigated. We find that the observed voltage shows a unique angular dependence and originates from ...the heat combined with the anomalous Nernst effect and the inverse spin Hall effect. From the analysis, Joule heating due to the high-frequency current in a Cu waveguide and the magnetization damping due to the precessional motion at off-resonant state are found to contribute to the heat source for the magneto-thermo electric signal. The results observed in CoFeB/Pt bilayer system also totally agree with the present scenario. This result provides an important aspect in future energy harvesting devices based on spin.
We experimentally show that half-metallic Co2MnSi films can be grown on SrTiO3(001) at around 350 °C by molecular beam epitaxy. Despite relatively low-temperature grown Co2MnSi films, L21-ordered ...structures, high saturation magnetic moments of ∼5.0 μB/f.u., and the negative sign of the anisotropic magnetoresistance (AMR) indicating half-metallic nature are obtained. For the 350°C-grown Co2MnSi films, a low Gilbert damping constant of ∼0.0035, implying the high spin polarization, is evaluated. This study will open a way for developing novel spintronic applications consisting of Co2MnSi and perovskite oxides such as high-performance interfacial multiferroic systems and efficient spin-to-charge conversion systems.
•Half-metallic Co2MnSi films can be grown on SrTiO3(001) at around 350 °C by MBE.•High L21-ordered structures with a saturation magnetic moment of ∼5.0 μB/f.u. are obtained.•Negative anisotropic magnetoresistance implying half-metallic nature is observed.•A low Gilbert damping constant of ∼0.0035 is evaluated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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