Introduction:Nitrogen enrichment of coastal salt marshes can induce feedbacks that alter ecosystem-level processes including primary production and carbon sequestration.Despite the rising interest in coastal blue carb...Introduction:Nitrogen enrichment of coastal salt marshes can induce feedbacks that alter ecosystem-level processes including primary production and carbon sequestration.Despite the rising interest in coastal blue carbon,the effects of chronic nutrient enrichment on blue carbon processes have rarely been measured in the context of experimental fertilization.Here,we examined the ecosystem-level effects of nitrate(NO3)enrichment on the green-house gas dynamics of a Spartina alterniflora-dominated salt marsh.We measured CO2 and CH4 fluxes using static chambers through two growing seasons in a salt marsh that was nitrogen-enriched for 13 years and compared fluxes to those from a reference marsh.Outcomes:We found that nitrogen enrichment increased gross primary productivity(GPP)by 7.7%and increased ecosystem respiration(Recd)by 20.8%.However,nitrogen enrichment had no discernible effect on net ecosystem exchange(NEE).Taken together,these results suggest that nitrogen-induced stimulation of Reco could transform this salt marsh from a carbon sink into a source of carbon to the atmos phere.Conclusion:Our results complement prior findings of nitrogen enrichment weakening soil structure and organic matter stability in tidal salt marshes,suggesting that increased nutrient inputs have the potential to alter the carbon storage function of these ecosystems through enhanced microbial respiration of previously sequestered carbon.展开更多
We report a theory of thermal spin pumping into proximity magnets under a transverse-bias-driven heat flow of magnons in magnetic films when the dipolar coupling to the magnetic gate is tuned to be “chiral”. While t...We report a theory of thermal spin pumping into proximity magnets under a transverse-bias-driven heat flow of magnons in magnetic films when the dipolar coupling to the magnetic gate is tuned to be “chiral”. While there is no rectification of the magnon current in the film, we predict that chirality diverts a large percentage(50% for perfect chirality) of it into the gate. This transverse thermal spin pumping effect can be controlled by rotating the film magnetization and may help manage the heat flow in future magnonic circuits.展开更多
Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to d...Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics.Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths.Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation.The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian.Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.展开更多
The duality between electric and magnetic dipoles inspires recent comparisons between ferronics and magnonics.Here we predict surface polarization waves or“ferrons”in ferroelectric insulators,taking the long-range d...The duality between electric and magnetic dipoles inspires recent comparisons between ferronics and magnonics.Here we predict surface polarization waves or“ferrons”in ferroelectric insulators,taking the long-range dipolar interaction into account.We predict properties that are strikingly different from the magnetic counterpart,i.e.the surface Damon-Eshbach magnons in ferromagnets.The dipolar interaction pushes the ferron branch with locked circular polarization and momentum to the ionic plasma frequency.The low-frequency modes are on the other hand in-plane polarized normal to their wave vectors.The strong anisotropy of the lower branch renders directional emissions of electric polarization and chiral near fields when activated by a focused laser beam,allowing optical routing in ferroelectric devices.展开更多
Thomson[1],the later Lord Kelvin,reported an increased electric resistance in iron and nickel when the magnetization is parallel rather than normal to the current direction,an effect now called anisotropic magnetoresi...Thomson[1],the later Lord Kelvin,reported an increased electric resistance in iron and nickel when the magnetization is parallel rather than normal to the current direction,an effect now called anisotropic magnetoresistance(AMR).The AMR allows sensing magnetic fields by simply measuring the resistance change when the magnetization realigns.While the magnetoresistance of magnetic tunnel junctions is larger,AMR sensors are attractive by their simplicity and robustness.展开更多
基金Funding for this project was provided by the National Science Foundation[award DEB-1354124 to TJM,award DEB-1719621 to the TIDE Project,and awards DEB-1637630&DEB-1238212 to the PIE-LTER].The study was further supported by startup funds from Bryn Mawr College to TJM.
文摘Introduction:Nitrogen enrichment of coastal salt marshes can induce feedbacks that alter ecosystem-level processes including primary production and carbon sequestration.Despite the rising interest in coastal blue carbon,the effects of chronic nutrient enrichment on blue carbon processes have rarely been measured in the context of experimental fertilization.Here,we examined the ecosystem-level effects of nitrate(NO3)enrichment on the green-house gas dynamics of a Spartina alterniflora-dominated salt marsh.We measured CO2 and CH4 fluxes using static chambers through two growing seasons in a salt marsh that was nitrogen-enriched for 13 years and compared fluxes to those from a reference marsh.Outcomes:We found that nitrogen enrichment increased gross primary productivity(GPP)by 7.7%and increased ecosystem respiration(Recd)by 20.8%.However,nitrogen enrichment had no discernible effect on net ecosystem exchange(NEE).Taken together,these results suggest that nitrogen-induced stimulation of Reco could transform this salt marsh from a carbon sink into a source of carbon to the atmos phere.Conclusion:Our results complement prior findings of nitrogen enrichment weakening soil structure and organic matter stability in tidal salt marshes,suggesting that increased nutrient inputs have the potential to alter the carbon storage function of these ecosystems through enhanced microbial respiration of previously sequestered carbon.
基金supported by the National Key Research and Development Program of China (Grant No. 2023YFA1406600)the National Natural Science Foundation of China (Grant No. 12374109)the startup grant of Huazhong University of Science and Technology, as well as JSPS KAKENHI (Grant Nos. 19H00645, and 22H04965)
文摘We report a theory of thermal spin pumping into proximity magnets under a transverse-bias-driven heat flow of magnons in magnetic films when the dipolar coupling to the magnetic gate is tuned to be “chiral”. While there is no rectification of the magnon current in the film, we predict that chirality diverts a large percentage(50% for perfect chirality) of it into the gate. This transverse thermal spin pumping effect can be controlled by rotating the film magnetization and may help manage the heat flow in future magnonic circuits.
基金We wish to acknowledge the support by the National Key Research and Development Program of China(Nos.2016YFA0300802 and 2017YFA0206200)the National Natural Science Foundation of China(NSFC)(Nos.11674020,12074026 and U1801661)+6 种基金the 111 talent program B16001G.B.was supported by the Netherlands Organization for Scientific Research(NWO)and Japan Society for the Promotion of Science Kakenhi Grants-in-Aid for Scientific Research(No.19H006450)T.Y.was funded through the Emmy Noether Program of Deutsche Forschungsgemeinschaft(SE 2558/2-1)K.X.thanks the National Key Research and Development Program of China(Nos.2017YFA0303304 and 2018YFB0407601)the National Natural Science Foundation of China(Nos.61774017 and 11734004)K.S.was supported by the Fundamental Research Funds for the Central Universities(No.2018EYT02)M.Z.W.were supported by the US National Science Foundation(No.EFMA-1641989).
文摘Nanomagnets are widely used to store information in non-volatile spintronic devices.Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport.However,to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics.Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths.Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation.The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian.Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.
基金financially supported by the National Natural Science Foundation of China(Grant No.0214012051)the startup grant of Huazhong University of Science and Technology(Grants Nos.3004012185,3004012198)+5 种基金the financial support by JSPS KAKENHI(Grant Nos.19H00645,22H04965)financially supported in Brazil by Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)Coordenac ao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)Financiadora de Estudos e Projetos(FINEP)Fundac ao de AmparoáCiencia e Tecnologia do Estado de Pernambuco(FACEPE)in Chile by Fondo Nacional de Desarrollo Científico y Tecnológico(FONDECYT)(Grant No.1210641)。
文摘The duality between electric and magnetic dipoles inspires recent comparisons between ferronics and magnonics.Here we predict surface polarization waves or“ferrons”in ferroelectric insulators,taking the long-range dipolar interaction into account.We predict properties that are strikingly different from the magnetic counterpart,i.e.the surface Damon-Eshbach magnons in ferromagnets.The dipolar interaction pushes the ferron branch with locked circular polarization and momentum to the ionic plasma frequency.The low-frequency modes are on the other hand in-plane polarized normal to their wave vectors.The strong anisotropy of the lower branch renders directional emissions of electric polarization and chiral near fields when activated by a focused laser beam,allowing optical routing in ferroelectric devices.
文摘Thomson[1],the later Lord Kelvin,reported an increased electric resistance in iron and nickel when the magnetization is parallel rather than normal to the current direction,an effect now called anisotropic magnetoresistance(AMR).The AMR allows sensing magnetic fields by simply measuring the resistance change when the magnetization realigns.While the magnetoresistance of magnetic tunnel junctions is larger,AMR sensors are attractive by their simplicity and robustness.
