Shengxian Wu, Oscar Hsu-Cheng Cheng, B. Zhao, Nicki Hogan, An-Tse Lee, D. Son, M. Sheldon
Recent studies have established that the anti-Stokes Raman signal from plasmonic metal nanostructures can be used to determine the two separate temperatures that characterize carriers inside the metal -- the temperature of photoexcited "hot carriers" and carriers that are thermalized with the metal lattice. However, the related signal in the Stokes spectral region has historically impeded surface enhanced Raman spectroscopy (SERS), as the vibrational peaks of adsorbed molecules are always accompanied by the broad background of the metal substrate. The fundamental source of the metal signal, and hence its contribution to the spectrum, has been unclear. Here, we outline a unified theoretical model that describes both the temperature-dependent behavior and the broad spectral distribution. We suggest that the majority of the Raman signal is from inelastic scattering directly with non-thermal carriers that have been excited via damping of the surface plasmon. In addition, a significant spectral component (~ 1%) is due to a sub-population of hot carriers in an elevated thermal distribution. We have performed temperature and power-dependent Raman experiments to show how a simple fitting procedure reveals the plasmon dephasing time, as well as the temperatures of the hot carriers and the metal lattice, in order to correlate these parameters with quantitative Raman analysis of chemical species adsorbed on metal surface.
{"title":"The connection between plasmon decay dynamics and the surface enhanced Raman spectroscopy background: Inelastic scattering from non-thermal and hot carriers","authors":"Shengxian Wu, Oscar Hsu-Cheng Cheng, B. Zhao, Nicki Hogan, An-Tse Lee, D. Son, M. Sheldon","doi":"10.1063/5.0032763","DOIUrl":"https://doi.org/10.1063/5.0032763","url":null,"abstract":"Recent studies have established that the anti-Stokes Raman signal from plasmonic metal nanostructures can be used to determine the two separate temperatures that characterize carriers inside the metal -- the temperature of photoexcited \"hot carriers\" and carriers that are thermalized with the metal lattice. However, the related signal in the Stokes spectral region has historically impeded surface enhanced Raman spectroscopy (SERS), as the vibrational peaks of adsorbed molecules are always accompanied by the broad background of the metal substrate. The fundamental source of the metal signal, and hence its contribution to the spectrum, has been unclear. Here, we outline a unified theoretical model that describes both the temperature-dependent behavior and the broad spectral distribution. We suggest that the majority of the Raman signal is from inelastic scattering directly with non-thermal carriers that have been excited via damping of the surface plasmon. In addition, a significant spectral component (~ 1%) is due to a sub-population of hot carriers in an elevated thermal distribution. We have performed temperature and power-dependent Raman experiments to show how a simple fitting procedure reveals the plasmon dephasing time, as well as the temperatures of the hot carriers and the metal lattice, in order to correlate these parameters with quantitative Raman analysis of chemical species adsorbed on metal surface.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89595497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of neck extensions in single and multi-degree of freedom Helmholtz resonator based acoustic liners is studied both experimentally and numerically and the resulting transmission coefficient and resonance frequencies are examined. It has been shown that a single degree of freedom liner with increasing neck extension lengths leads to the resonance frequencies being pushed to lower frequency values, however, this shift to lower frequencies is not linear with increasing length. A study on including neck extensions for the primary and/or secondary neck within a double degree of freedom liner is also presented. It is shown that both neck extension concepts lead to an increase in bandwidth of sound absorption by a double degree of freedom Helmholtz resonator.
{"title":"An Investigation On Neck Extensions For Single and Multi-Degree Of Freedom Acoustic Helmholtz Resonators","authors":"A. Gautam, A. Celik, M. Azarpeyvand","doi":"10.2514/6.2021-2206","DOIUrl":"https://doi.org/10.2514/6.2021-2206","url":null,"abstract":"The effect of neck extensions in single and multi-degree of freedom Helmholtz resonator based acoustic liners is studied both experimentally and numerically and the resulting transmission coefficient and resonance frequencies are examined. It has been shown that a single degree of freedom liner with increasing neck extension lengths leads to the resonance frequencies being pushed to lower frequency values, however, this shift to lower frequencies is not linear with increasing length. A study on including neck extensions for the primary and/or secondary neck within a double degree of freedom liner is also presented. It is shown that both neck extension concepts lead to an increase in bandwidth of sound absorption by a double degree of freedom Helmholtz resonator.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73876534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuanyuan Zhang, Xiaoqing Sun, Junshuai Chai, Hao Xu, Xueli Ma, J. Xiang, Kai Han, Xiaolei Wang, Wenwu Wang
This paper investigates the thermodynamic driving force of transient negative capacitance (NC) in the series circuit of the resistor and ferroelectric capacitor (R-FEC). We find that the widely used Landau-Khalatnikov (L-K) theory, that is, the minimum of the Gibbs free energy, is inapplicable to explain the transient NC. The thermodynamic driving force of the transient NC phenomenon is the minimum of the difference between the elastic Gibbs free energy and the electric polarization work. The appearance of the transient NC phenomenon is not due to the widely accepted view that the ferroelectric polarization goes through the negative curvature region of elastic Gibbs free energy landscape (Ga). Instead, the transient NC phenomenon appears when the energy barrier of Ga disappears. The transient NC is dependent on both the intrinsic ferroelectric material parameters and extrinsic factors in the R-FEC circuit.
{"title":"Thermodynamic driving force of transient negative capacitance of ferroelectric capacitors","authors":"Yuanyuan Zhang, Xiaoqing Sun, Junshuai Chai, Hao Xu, Xueli Ma, J. Xiang, Kai Han, Xiaolei Wang, Wenwu Wang","doi":"10.1063/5.0039246","DOIUrl":"https://doi.org/10.1063/5.0039246","url":null,"abstract":"This paper investigates the thermodynamic driving force of transient negative capacitance (NC) in the series circuit of the resistor and ferroelectric capacitor (R-FEC). We find that the widely used Landau-Khalatnikov (L-K) theory, that is, the minimum of the Gibbs free energy, is inapplicable to explain the transient NC. The thermodynamic driving force of the transient NC phenomenon is the minimum of the difference between the elastic Gibbs free energy and the electric polarization work. The appearance of the transient NC phenomenon is not due to the widely accepted view that the ferroelectric polarization goes through the negative curvature region of elastic Gibbs free energy landscape (Ga). Instead, the transient NC phenomenon appears when the energy barrier of Ga disappears. The transient NC is dependent on both the intrinsic ferroelectric material parameters and extrinsic factors in the R-FEC circuit.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82401571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of pulsed laser polishing on rough niobium surfaces was investigated. We created different well-defined roughness profiles with standard emery papers and subsequently remelted random surface areas with a size of about 2x2 mm^2 with nanosecond laser pulses (wavelength of 1064 nm, pulse length of 10 ns). Pristine as well as laser-treated surfaces were investigated using optical profilometry and atomic force microscopy, and the surface topography was described by means of correlation functions. Uniformly rough and highly smooth surface geometries were achieved for fractals above and below 7 {mu}m, respectively. Moreover, the behavior of foreign particles during the laser processing was investigated in detail. The polishing procedure was also monitored point by point by detecting electrical signals, i.e., sample charging, which resulted from the intense laser illumination. The measured electrical charges were found to be correlated with the local surface texture. Thus, regions with initially high roughness profiles and regions with extensive laser-induced defects could be directly identified from the detected electrical signals.
{"title":"Laser-processing of grinded and mechanically abraded Nb-surfaces","authors":"V. Porshyn, P. Rothweiler, D. Lützenkirchen-Hecht","doi":"10.2351/7.0000160","DOIUrl":"https://doi.org/10.2351/7.0000160","url":null,"abstract":"The effect of pulsed laser polishing on rough niobium surfaces was investigated. We created different well-defined roughness profiles with standard emery papers and subsequently remelted random surface areas with a size of about 2x2 mm^2 with nanosecond laser pulses (wavelength of 1064 nm, pulse length of 10 ns). Pristine as well as laser-treated surfaces were investigated using optical profilometry and atomic force microscopy, and the surface topography was described by means of correlation functions. Uniformly rough and highly smooth surface geometries were achieved for fractals above and below 7 {mu}m, respectively. Moreover, the behavior of foreign particles during the laser processing was investigated in detail. The polishing procedure was also monitored point by point by detecting electrical signals, i.e., sample charging, which resulted from the intense laser illumination. The measured electrical charges were found to be correlated with the local surface texture. Thus, regions with initially high roughness profiles and regions with extensive laser-induced defects could be directly identified from the detected electrical signals.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83358597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Henry Navarro, J. D. Valle, Y. Kalcheim, N. Vargas, C. Adda, Min-Han Lee, P. Lapa, A. Rivera‐Calzada, I. Zaluzhnyy, Erbin Qiu, O. Shpyrko, M. Rozenberg, A. Frano, I. Schuller
The coupling of electronic degrees of freedom in materials to create hybridized functionalities is a holy grail of modern condensed matter physics that may produce novel mechanisms of control. Correlated electron systems often exhibit coupled degrees of freedom with a high degree of tunability which sometimes lead to hybridized functionalities based on external stimuli. However, the mechanisms of tunability and the sensitivity to external stimuli are determined by intrinsic material properties which are not always controllable. A Mott metal-insulator transition, which is technologically attractive due to the large changes in resistance, can be tuned by doping, strain, electric fields, and orbital occupancy but cannot be, in and of itself, controlled externally with light. Here we present a new approach to produce hybridized functionalities using a properly engineered photoconductor/strongly-correlated hybrid heterostructure, showing control of the Metal-to-Insulator transition (MIT) using optical means. This approach combines a photoconductor, which does not exhibit an MIT, with a strongly correlated oxide, which is not photoconducting. Due to the close proximity between the two materials, the heterostructure exhibits large volatile and nonvolatile, photoinduced resistivity changes and substantial photoinduced shifts in the MIT transition temperatures. This approach can potentially be extended to other judiciously chosen combinations of strongly correlated materials with systems which exhibit optically, electrically or magnetically controllable behavior.
{"title":"A hybrid optoelectronic Mott insulator","authors":"Henry Navarro, J. D. Valle, Y. Kalcheim, N. Vargas, C. Adda, Min-Han Lee, P. Lapa, A. Rivera‐Calzada, I. Zaluzhnyy, Erbin Qiu, O. Shpyrko, M. Rozenberg, A. Frano, I. Schuller","doi":"10.1063/5.0044066","DOIUrl":"https://doi.org/10.1063/5.0044066","url":null,"abstract":"The coupling of electronic degrees of freedom in materials to create hybridized functionalities is a holy grail of modern condensed matter physics that may produce novel mechanisms of control. Correlated electron systems often exhibit coupled degrees of freedom with a high degree of tunability which sometimes lead to hybridized functionalities based on external stimuli. However, the mechanisms of tunability and the sensitivity to external stimuli are determined by intrinsic material properties which are not always controllable. A Mott metal-insulator transition, which is technologically attractive due to the large changes in resistance, can be tuned by doping, strain, electric fields, and orbital occupancy but cannot be, in and of itself, controlled externally with light. Here we present a new approach to produce hybridized functionalities using a properly engineered photoconductor/strongly-correlated hybrid heterostructure, showing control of the Metal-to-Insulator transition (MIT) using optical means. This approach combines a photoconductor, which does not exhibit an MIT, with a strongly correlated oxide, which is not photoconducting. Due to the close proximity between the two materials, the heterostructure exhibits large volatile and nonvolatile, photoinduced resistivity changes and substantial photoinduced shifts in the MIT transition temperatures. This approach can potentially be extended to other judiciously chosen combinations of strongly correlated materials with systems which exhibit optically, electrically or magnetically controllable behavior.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74859619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-27DOI: 10.1061/9780784483374.100
Muhao Chen, R. Goyal, M. Majji, R. Skelton
A tensegrity tower design to support a given payload for the moon mining operation is proposed in this paper. A non-linear optimization problem for the minimal-mass structure design is posed and solved, subject to the yielding constraints for strings and yielding and buckling constraints for bars in the presence of lunar gravity. The optimization variables for this non-linear problem are structural complexity and pre-stress in the strings. Apart from local failure constraints of yielding and buckling, global buckling is also considered. The structure designed as a deployable tower is a TnD1 tensegrity structure. A case study demonstrates the feasibility and advantage of the tower design. The principles developed in this paper are also applicable for building other structures on the Earth or other planets.
{"title":"Deployable Tensegrity Lunar Tower","authors":"Muhao Chen, R. Goyal, M. Majji, R. Skelton","doi":"10.1061/9780784483374.100","DOIUrl":"https://doi.org/10.1061/9780784483374.100","url":null,"abstract":"A tensegrity tower design to support a given payload for the moon mining operation is proposed in this paper. A non-linear optimization problem for the minimal-mass structure design is posed and solved, subject to the yielding constraints for strings and yielding and buckling constraints for bars in the presence of lunar gravity. The optimization variables for this non-linear problem are structural complexity and pre-stress in the strings. Apart from local failure constraints of yielding and buckling, global buckling is also considered. The structure designed as a deployable tower is a TnD1 tensegrity structure. A case study demonstrates the feasibility and advantage of the tower design. The principles developed in this paper are also applicable for building other structures on the Earth or other planets.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87547962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Fedchak, J. Scherschligt, S. Avdiaj, D. Barker, S. Eckel, B. Bowers, Scott OConnell, Perry A. Henderson
We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat treatments. Chambers of five different materials were tested: 304L, 316L, and 316LN stainless steels; titanium; and aluminum. In addition, chambers constructed of 316L and 316LN stainless steel were subjected to a vacuum-fire process, where they were heated to approximately 950 °C for 24 hours while under vacuum. These latter two chambers are designated as 316L-XHV and 316LN-XHV. Because all the chambers were of identical geometry and made by the same manufacturer, a relative comparison of the outgassing rates among these chambers can be made. Water outgassing rates were measured as a function of time using the throughput technique. The water outgassing results for the 316L, 316LN, 316L-XHV, 316LN-XHV were all similar, but lower than those of 304L by a factor of 3 to 5 lower at 10,000 s. The water outgassing results for Ti and Al chambers were closer to that of 304L, Ti being slightly lower. Hydrogen outgassing rates were measured using the rate-of-rise method and performed after a low-temperature bake of 125 °C to 150 °C for a minimum of 72 hours. The Ti, Al, 316L-XHV, and 316LN-XHV chambers all have ultra-low specific outgassing rates below 1.0E-11 Pa L s-1 cm-2 and are a factor of 100 or better than the 304L chamber. The 304L, 316L, and 316LN chambers with no vacuum-fire heat treatment have larger hydrogen outgassing rates than the other chambers, with determined specific outgassing rates ranging between 4.0E-11 Pa L s-1 cm-2 and 8.0E-11 Pa L s-1 cm-2. We conclude that Ti, Al, 316L-XHV, and 316LN-XHV have hydrogen outgassing rates that make them excellent choices for ultra-high vacuum (UHV) and extreme-high vacuum (XHV) applications, the choice depending on cost and other material properties.
我们测量了七个几何形状相同但材料和热处理方式不同的真空室的水和氢放气率。测试了五种不同材料的腔室:304L, 316L和316LN不锈钢;钛;和铝。此外，由316L和316LN不锈钢制成的腔室经受真空火处理，在真空下加热到大约950°C 24小时。后两个室被指定为316L-XHV和316LN-XHV。由于所有的腔室都是相同的几何形状，由同一制造商制造，因此可以对这些腔室的放气速率进行相对比较。利用通量技术测量出水率作为时间的函数。316L、316LN、316L- xhv、316LN- xhv的脱气结果相似，但在10000 s时比304L的脱气结果低3 ~ 5倍。Ti和Al气室的放水结果与304L气室的放水结果接近，Ti气室的放水结果略低。在125°C至150°C的低温烘烤至少72小时后，使用上升速率法测量氢气放气率。Ti、Al、316L-XHV和316LN-XHV气室都具有低于1.0E-11 Pa L s-1 cm-2的超低比放气率，比304L气室低100倍或更好。没有真空火热处理的304L、316L和316LN燃烧室比其他燃烧室有更大的氢气放气速率，确定的比放气速率在4.0E-11 Pa L s-1 cm-2和8.0E-11 Pa L s-1 cm-2之间。我们得出的结论是，Ti, Al, 316L-XHV和316LN-XHV具有氢气放气率，使其成为超高真空(UHV)和极高真空(XHV)应用的绝佳选择，选择取决于成本和其他材料性能。
{"title":"Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments","authors":"J. Fedchak, J. Scherschligt, S. Avdiaj, D. Barker, S. Eckel, B. Bowers, Scott OConnell, Perry A. Henderson","doi":"10.1116/6.0000657","DOIUrl":"https://doi.org/10.1116/6.0000657","url":null,"abstract":"We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat treatments. Chambers of five different materials were tested: 304L, 316L, and 316LN stainless steels; titanium; and aluminum. In addition, chambers constructed of 316L and 316LN stainless steel were subjected to a vacuum-fire process, where they were heated to approximately 950 °C for 24 hours while under vacuum. These latter two chambers are designated as 316L-XHV and 316LN-XHV. Because all the chambers were of identical geometry and made by the same manufacturer, a relative comparison of the outgassing rates among these chambers can be made. Water outgassing rates were measured as a function of time using the throughput technique. The water outgassing results for the 316L, 316LN, 316L-XHV, 316LN-XHV were all similar, but lower than those of 304L by a factor of 3 to 5 lower at 10,000 s. The water outgassing results for Ti and Al chambers were closer to that of 304L, Ti being slightly lower. Hydrogen outgassing rates were measured using the rate-of-rise method and performed after a low-temperature bake of 125 °C to 150 °C for a minimum of 72 hours. The Ti, Al, 316L-XHV, and 316LN-XHV chambers all have ultra-low specific outgassing rates below 1.0E-11 Pa L s-1 cm-2 and are a factor of 100 or better than the 304L chamber. The 304L, 316L, and 316LN chambers with no vacuum-fire heat treatment have larger hydrogen outgassing rates than the other chambers, with determined specific outgassing rates ranging between 4.0E-11 Pa L s-1 cm-2 and 8.0E-11 Pa L s-1 cm-2. We conclude that Ti, Al, 316L-XHV, and 316LN-XHV have hydrogen outgassing rates that make them excellent choices for ultra-high vacuum (UHV) and extreme-high vacuum (XHV) applications, the choice depending on cost and other material properties.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88312326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Vilela, J. E. Abrão, E. Santos, Y. Yao, J. Mendes, R. L. Rodríguez-Suárez, S. Rezende, W. Han, A. Azevedo, J. Moodera
The control of pure spin currents carried by magnons in magnetic insulator (MI) garnet films with a robust perpendicular magnetic anisotropy (PMA) is of great interest to spintronic technology as they can be used to carry, transport and process information. Garnet films with PMA present labyrinth domain magnetic structures that enrich the magnetization dynamics, and could be employed in more efficient wave-based logic and memory computing devices. In MI/NM bilayers, where NM being a normal metal providing a strong spin-orbit coupling, the PMA benefits the spin-orbit torque (SOT) driven magnetization's switching by lowering the needed current and rendering the process faster, crucial for developing magnetic random-access memories (SOT-MRAM). In this work, we investigated the magnetic anisotropies in thulium iron garnet (TIG) films with PMA via ferromagnetic resonance measurements, followed by the excitation and detection of magnon-mediated pure spin currents in TIG/Pt driven by microwaves and heat currents. TIG films presented a Gilbert damping constant {alpha}~0.01, with resonance fields above 3.5 kOe and half linewidths broader than 60 Oe, at 300 K and 9.5 GHz. The spin-to-charge current conversion through TIG/Pt was observed as a micro-voltage generated at the edges of the Pt film. The obtained spin Seebeck coefficient was 0.54 {mu}V/K, confirming also the high interfacial spin transparency.
{"title":"Magnon-mediated spin currents in Tm3Fe5O12/Pt with perpendicular magnetic anisotropy","authors":"G. Vilela, J. E. Abrão, E. Santos, Y. Yao, J. Mendes, R. L. Rodríguez-Suárez, S. Rezende, W. Han, A. Azevedo, J. Moodera","doi":"10.1063/5.0023242","DOIUrl":"https://doi.org/10.1063/5.0023242","url":null,"abstract":"The control of pure spin currents carried by magnons in magnetic insulator (MI) garnet films with a robust perpendicular magnetic anisotropy (PMA) is of great interest to spintronic technology as they can be used to carry, transport and process information. Garnet films with PMA present labyrinth domain magnetic structures that enrich the magnetization dynamics, and could be employed in more efficient wave-based logic and memory computing devices. In MI/NM bilayers, where NM being a normal metal providing a strong spin-orbit coupling, the PMA benefits the spin-orbit torque (SOT) driven magnetization's switching by lowering the needed current and rendering the process faster, crucial for developing magnetic random-access memories (SOT-MRAM). In this work, we investigated the magnetic anisotropies in thulium iron garnet (TIG) films with PMA via ferromagnetic resonance measurements, followed by the excitation and detection of magnon-mediated pure spin currents in TIG/Pt driven by microwaves and heat currents. TIG films presented a Gilbert damping constant {alpha}~0.01, with resonance fields above 3.5 kOe and half linewidths broader than 60 Oe, at 300 K and 9.5 GHz. The spin-to-charge current conversion through TIG/Pt was observed as a micro-voltage generated at the edges of the Pt film. The obtained spin Seebeck coefficient was 0.54 {mu}V/K, confirming also the high interfacial spin transparency.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78632161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improvement of tool reliability and uptime is a current focus in development of extreme ultraviolet lithography. The lifetime of collection mirrors for extreme ultraviolet light in tin-based plasma light sources is limited considerably by contamination with thick tin deposits that cannot be removed sufficiently fast by plasma etching. For tin droplet splats sticking to large substrates, we have developed and compared several efficient cleaning techniques based on cryogenic cooling. A silicon carbide substrate and different silicon wafer samples with up to 6 inch diameter with the surface uncoated, multilayer-coated, unstructured and grating-structured were tested. After tin dripping onto heated samples, embrittlement of droplet contamination is induced in-situ by stresses during phase transformation, following the initiation of tin pest with seed crystals of gray tin. Conversion of initially adhesive deposits to loose gray tin has been reached in less than 24 hours on all tested surfaces by continuous cooling with cold nitrogen vapor to temperatures in the range of -30 to -50 °C. Alternatively, stress-initiated tin-removal by delamination of beta-Sn droplet splats has been attained via contraction strain induced by strong cooling to temperatures of around -120 °C. Profilometry has been used to analyze the bottom side of tin droplet splats removed from a grating-structured wafer. The in-situ tin cleaning techniques give results comparable to fast ex-situ cleaning that has been achieved either by sample immersion in liquid nitrogen or by splat removal after CO2 snowflake aerosol impact using a hand-held jet-nozzle. The implementation of the in-situ phase-conversion concept for the cleaning of collector mirrors in commercial light sources for lithography is discussed.
{"title":"Cryogenic cleaning of tin-drop contamination on surfaces relevant for extreme ultraviolet light collection","authors":"N. Böwering, C. Meier","doi":"10.1116/6.0000501","DOIUrl":"https://doi.org/10.1116/6.0000501","url":null,"abstract":"Improvement of tool reliability and uptime is a current focus in development of extreme ultraviolet lithography. The lifetime of collection mirrors for extreme ultraviolet light in tin-based plasma light sources is limited considerably by contamination with thick tin deposits that cannot be removed sufficiently fast by plasma etching. For tin droplet splats sticking to large substrates, we have developed and compared several efficient cleaning techniques based on cryogenic cooling. A silicon carbide substrate and different silicon wafer samples with up to 6 inch diameter with the surface uncoated, multilayer-coated, unstructured and grating-structured were tested. After tin dripping onto heated samples, embrittlement of droplet contamination is induced in-situ by stresses during phase transformation, following the initiation of tin pest with seed crystals of gray tin. Conversion of initially adhesive deposits to loose gray tin has been reached in less than 24 hours on all tested surfaces by continuous cooling with cold nitrogen vapor to temperatures in the range of -30 to -50 °C. Alternatively, stress-initiated tin-removal by delamination of beta-Sn droplet splats has been attained via contraction strain induced by strong cooling to temperatures of around -120 °C. Profilometry has been used to analyze the bottom side of tin droplet splats removed from a grating-structured wafer. The in-situ tin cleaning techniques give results comparable to fast ex-situ cleaning that has been achieved either by sample immersion in liquid nitrogen or by splat removal after CO2 snowflake aerosol impact using a hand-held jet-nozzle. The implementation of the in-situ phase-conversion concept for the cleaning of collector mirrors in commercial light sources for lithography is discussed.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90541124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：