K. K. Pandey, Valery I. Levitas, Changyong Park, Guoyin Shen
The detailed study of the effect of the initial microstructure on its evolution under hydrostatic compression before, during, and after the irreversible α→ω phase transformation and during pressure release in Zr using in situ x-ray diffraction is presented. Two samples were studied: one is plastically pre-deformed Zr with saturated hardness and the other is annealed. Phase transformation α→ω initiates at lower pressure for a pre-deformed sample but for a volume fraction of ω Zr, c>0.7, a larger volume fraction is observed for the annealed sample. This implies that the proportionality between the athermal resistance to the transformation and the yield strength in the continuum phase transformation theory is invalid; an advanced version of the theory is outlined. Phenomenological plasticity theory under hydrostatic loading is outlined in terms of microstructural parameters, and plastic strain is estimated. During transformation, the first rule is suggested, i.e., the average domain size, microstrain, and dislocation density in ω Zr for c<0.8 are functions of the volume fraction, c of ω Zr only, which are independent of the plastic strain tensor prior to transformation and pressure. The microstructure is not inherited during phase transformation. Surprisingly, for the annealed sample, the final dislocation density and the average microstrain after pressure release in the ω phase are larger than for the severely pre-deformed sample. The results suggest that an extended experimental basis is required for the predictive models for the combined pressure-induced phase transformations and microstructure evolutions.
{"title":"In situ study of microstructure evolution and α → ω phase transition in annealed and pre-deformed Zr under hydrostatic loading","authors":"K. K. Pandey, Valery I. Levitas, Changyong Park, Guoyin Shen","doi":"10.1063/5.0208544","DOIUrl":"https://doi.org/10.1063/5.0208544","url":null,"abstract":"The detailed study of the effect of the initial microstructure on its evolution under hydrostatic compression before, during, and after the irreversible α→ω phase transformation and during pressure release in Zr using in situ x-ray diffraction is presented. Two samples were studied: one is plastically pre-deformed Zr with saturated hardness and the other is annealed. Phase transformation α→ω initiates at lower pressure for a pre-deformed sample but for a volume fraction of ω Zr, c&gt;0.7, a larger volume fraction is observed for the annealed sample. This implies that the proportionality between the athermal resistance to the transformation and the yield strength in the continuum phase transformation theory is invalid; an advanced version of the theory is outlined. Phenomenological plasticity theory under hydrostatic loading is outlined in terms of microstructural parameters, and plastic strain is estimated. During transformation, the first rule is suggested, i.e., the average domain size, microstrain, and dislocation density in ω Zr for c&lt;0.8 are functions of the volume fraction, c of ω Zr only, which are independent of the plastic strain tensor prior to transformation and pressure. The microstructure is not inherited during phase transformation. Surprisingly, for the annealed sample, the final dislocation density and the average microstrain after pressure release in the ω phase are larger than for the severely pre-deformed sample. The results suggest that an extended experimental basis is required for the predictive models for the combined pressure-induced phase transformations and microstructure evolutions.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"22 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar-driven semiconductor photocatalysts are highly appealing in applications of environmental remediation and energy conversion. However, photocatalytic reactions, particularly oxygen evolution reaction (OER), are often constrained by the swift recombination of electron–hole pairs, thereby resulting in low reaction efficiency. Although it is effective to separate charge carriers by constructing heterojunctions to form built-in electric field, the lattice mismatch and inefficient interlayer charge transfer of heterojunctions in the photocatalysts limit their further development. Here, we propose a new strategy by constructing an internal electric field for OER through an individual piezoelectric two-dimensional material. The results indicate that the piezoelectric effect regulates the electronic structure, reduces bandgap, improves light absorption efficiency, and that the displacement of positive and negative charge centers is the key factor in the enhanced OER. This research indicates the feasibility of combining piezoelectric properties of two-dimensional materials with OER (1.19 eV), providing new insights and guidance for applying the piezoelectric effect in the OER and opening up a way to promote efficient separation of charge carriers.
太阳能驱动的半导体光催化剂在环境修复和能源转换应用中极具吸引力。然而，光催化反应，尤其是氧进化反应（OER），往往受到电子-空穴对迅速重组的限制，从而导致反应效率低下。虽然通过构建异质结形成内置电场来分离电荷载流子是有效的，但光催化剂中异质结的晶格失配和低效的层间电荷转移限制了其进一步发展。在此，我们提出了一种新策略，即通过单独的压电二维材料构建内部电场来实现 OER。研究结果表明，压电效应可以调节电子结构、减小带隙、提高光吸收率，而正负电荷中心的位移是增强 OER 的关键因素。该研究表明，将二维材料的压电特性与 OER（1.19 eV）相结合是可行的，为在 OER 中应用压电效应提供了新的见解和指导，并开辟了一条促进电荷载流子高效分离的途径。
{"title":"Piezo-photocatalysis synergy in γ-GeSe for highly efficient oxygen evolution reaction","authors":"Tianqi Zhang, Long Zhou, Guobo Chen, Songrui Wei, Rong Sun, Yunping Li, Lijian Meng, Guanglong Zhang, Shuwei Xia, Zhongchang Wang, Meng Qiu","doi":"10.1063/5.0217893","DOIUrl":"https://doi.org/10.1063/5.0217893","url":null,"abstract":"Solar-driven semiconductor photocatalysts are highly appealing in applications of environmental remediation and energy conversion. However, photocatalytic reactions, particularly oxygen evolution reaction (OER), are often constrained by the swift recombination of electron–hole pairs, thereby resulting in low reaction efficiency. Although it is effective to separate charge carriers by constructing heterojunctions to form built-in electric field, the lattice mismatch and inefficient interlayer charge transfer of heterojunctions in the photocatalysts limit their further development. Here, we propose a new strategy by constructing an internal electric field for OER through an individual piezoelectric two-dimensional material. The results indicate that the piezoelectric effect regulates the electronic structure, reduces bandgap, improves light absorption efficiency, and that the displacement of positive and negative charge centers is the key factor in the enhanced OER. This research indicates the feasibility of combining piezoelectric properties of two-dimensional materials with OER (1.19 eV), providing new insights and guidance for applying the piezoelectric effect in the OER and opening up a way to promote efficient separation of charge carriers.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"25 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic force microscopy (MFM) is long established as a powerful tool for probing the local stray fields of magnetic nanostructures across a range of temperatures and applied stimuli. A major drawback of the technique, however, is that the detection of stray fields emanating from a sample’s surface rely on a uniaxial vertical cantilever oscillation, and thus are only sensitive to vertically oriented stray field components. The last two decades have shown an ever-increasing literature fascination for exotic topological windings where particular attention to in-plane magnetic moment rotation is highly valuable when identifying and understanding such systems. Here, we present a method of detecting in-plane magnetic stray field components, by utilizing a split-electrode excitation piezo that allows the simultaneous excitation of a cantilever at its fundamental flexural and torsional modes. This allows for the joint acquisition of traditional vertical mode images and a lateral MFM where the tip–cantilever system is only sensitive to stray fields acting perpendicular to the torsional axis of the cantilever.
{"title":"Toward 3D magnetic force microscopy: Simultaneous torsional cantilever excitation to access a second, orthogonal stray field component","authors":"Jori F. Schmidt, Lukas M. Eng, Samuel D. Seddon","doi":"10.1063/5.0226570","DOIUrl":"https://doi.org/10.1063/5.0226570","url":null,"abstract":"Magnetic force microscopy (MFM) is long established as a powerful tool for probing the local stray fields of magnetic nanostructures across a range of temperatures and applied stimuli. A major drawback of the technique, however, is that the detection of stray fields emanating from a sample’s surface rely on a uniaxial vertical cantilever oscillation, and thus are only sensitive to vertically oriented stray field components. The last two decades have shown an ever-increasing literature fascination for exotic topological windings where particular attention to in-plane magnetic moment rotation is highly valuable when identifying and understanding such systems. Here, we present a method of detecting in-plane magnetic stray field components, by utilizing a split-electrode excitation piezo that allows the simultaneous excitation of a cantilever at its fundamental flexural and torsional modes. This allows for the joint acquisition of traditional vertical mode images and a lateral MFM where the tip–cantilever system is only sensitive to stray fields acting perpendicular to the torsional axis of the cantilever.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"17 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although the global market for wind energy is growing rapidly, leading-edge erosion is a critical issue hindering the development of wind power. The impact force of a droplet colliding with flat surfaces has been investigated in previous studies. However, the impact force exerted on curved surfaces, such as that experienced by eroded wind turbine blades, is not well understood. This study discusses the relationship between the impact force generated on a solid surface by a water droplet and the radius of curvature of the impacting surface. The impact force by a droplet was measured using a force sensor mounted on semi-cylindrical caps with different radii of curvature. The measurement results showed that the impact force decreased as the radius of curvature decreased. A computational fluid dynamics model solving incompressible flows showed that, unlike the case of a curved surface, the initial momentum of the droplet was mostly transferred to the flat surface. This resulted in a high impulse for an impact with a flat surface. The falling droplet was blocked by the surface, and the lateral jet was accelerated sideward. This acceleration was moderate for curved surfaces. When colliding with a flat surface, a higher impact force was generated owing to the wider area of the excited surface pressure compared with that of the curved surface. Finally, the relationship between the peak of the impact force and the surface curvature was derived, suggesting that the force peak is inversely proportional to the curvature.
{"title":"Influence of surface curvature on the impact force of water droplet","authors":"A. Aihara, M. Tanaka, N. Fujisawa","doi":"10.1063/5.0219757","DOIUrl":"https://doi.org/10.1063/5.0219757","url":null,"abstract":"Although the global market for wind energy is growing rapidly, leading-edge erosion is a critical issue hindering the development of wind power. The impact force of a droplet colliding with flat surfaces has been investigated in previous studies. However, the impact force exerted on curved surfaces, such as that experienced by eroded wind turbine blades, is not well understood. This study discusses the relationship between the impact force generated on a solid surface by a water droplet and the radius of curvature of the impacting surface. The impact force by a droplet was measured using a force sensor mounted on semi-cylindrical caps with different radii of curvature. The measurement results showed that the impact force decreased as the radius of curvature decreased. A computational fluid dynamics model solving incompressible flows showed that, unlike the case of a curved surface, the initial momentum of the droplet was mostly transferred to the flat surface. This resulted in a high impulse for an impact with a flat surface. The falling droplet was blocked by the surface, and the lateral jet was accelerated sideward. This acceleration was moderate for curved surfaces. When colliding with a flat surface, a higher impact force was generated owing to the wider area of the excited surface pressure compared with that of the curved surface. Finally, the relationship between the peak of the impact force and the surface curvature was derived, suggesting that the force peak is inversely proportional to the curvature.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"3 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. V. Myasoedov, M. G. Mynbaeva, S. P. Lebedev, S. Iu. Priobrazhenskii, D. G. Amelchuk, D. A. Kirilenko, A. A. Lebedev
At present, intensive research is underway in the field of vacuum-sublimation growth of 3C-SiC. Transfer of a thin (001)3C-SiC layer onto a 6H-SiC wafer is a promising way to fabricate a 3C-SiC/6H-SiC substrate for growing device-quality homoepitaxial films of low defect density. The article presents the results of the structural characterization of an interface formed during the transfer of a 3C-SiC layer onto a 6H-SiC(0001) wafer, performed with transmission electron microscopy (TEM). A 3C-SiC film with a thickness of about 10 μm, grown by chemical vapor deposition (CVD) on a Si(001) substrate, was utilized in the study. Silicon acted as a bonding material in the transfer process. The morphology and microstructure of the interface between a 6H-SiC substrate and a 3C-SiC (001)-oriented layer are under consideration. TEM investigation reveals an effect of “self”-orientation of the layer with respect to the wafer during the transfer process: an interaction between the molten silicon layer and silicon carbide throughout crystallization results in the generation of defined orientation relationships with respect to substrate axes. An analysis of selected area electron diffraction patterns taken from interfaces showed the relationships to be 3C-SiC{001}‖ 6H-SiC(0001) and 3C-SiC⟨11¯0⟩∼‖ 6H-SiC⟨112¯0⟩.
{"title":"TEM investigation of the interface formation during transfer of 3C-SiC(001) layer onto 6H-SiC(0001) wafer","authors":"A. V. Myasoedov, M. G. Mynbaeva, S. P. Lebedev, S. Iu. Priobrazhenskii, D. G. Amelchuk, D. A. Kirilenko, A. A. Lebedev","doi":"10.1063/5.0227316","DOIUrl":"https://doi.org/10.1063/5.0227316","url":null,"abstract":"At present, intensive research is underway in the field of vacuum-sublimation growth of 3C-SiC. Transfer of a thin (001)3C-SiC layer onto a 6H-SiC wafer is a promising way to fabricate a 3C-SiC/6H-SiC substrate for growing device-quality homoepitaxial films of low defect density. The article presents the results of the structural characterization of an interface formed during the transfer of a 3C-SiC layer onto a 6H-SiC(0001) wafer, performed with transmission electron microscopy (TEM). A 3C-SiC film with a thickness of about 10 μm, grown by chemical vapor deposition (CVD) on a Si(001) substrate, was utilized in the study. Silicon acted as a bonding material in the transfer process. The morphology and microstructure of the interface between a 6H-SiC substrate and a 3C-SiC (001)-oriented layer are under consideration. TEM investigation reveals an effect of “self”-orientation of the layer with respect to the wafer during the transfer process: an interaction between the molten silicon layer and silicon carbide throughout crystallization results in the generation of defined orientation relationships with respect to substrate axes. An analysis of selected area electron diffraction patterns taken from interfaces showed the relationships to be 3C-SiC{001}‖ 6H-SiC(0001) and 3C-SiC⟨11¯0⟩∼‖ 6H-SiC⟨112¯0⟩.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"29 9 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Casolaro, V. Izzo, G. Giusi, N. Wyrsch, A. Aloisio
We investigated the capacitance of a forward-biased silicon pn diode using impedance spectroscopy. Despite extensive research spanning decades, no single model in the literature adequately describes the impedance behavior for bias up to the built-in voltage. By employing the 1N4007 diode as a case study, we analyzed the impedance over a wide frequency range, from 1 Hz to 1 MHz. Our analysis reveals that impedance can be effectively studied by combining two models. In both models, the depletion capacitance is assumed to be an ideal capacitor with a value independent of frequency. One model accounts for diffusion processes, while the other addresses interfacial effects, as well as potential and capacitance distributions across the junction. This approach offers valuable insights into the complex capacitance behavior of pn junctions as a function of the bias voltage. Measurements of depletion and diffusion capacitances, as well as of the diode transit time can be achieved from a set of impedance spectroscopy data.
{"title":"Modeling the diffusion and depletion capacitances of a silicon pn diode in forward bias with impedance spectroscopy","authors":"P. Casolaro, V. Izzo, G. Giusi, N. Wyrsch, A. Aloisio","doi":"10.1063/5.0230008","DOIUrl":"https://doi.org/10.1063/5.0230008","url":null,"abstract":"We investigated the capacitance of a forward-biased silicon pn diode using impedance spectroscopy. Despite extensive research spanning decades, no single model in the literature adequately describes the impedance behavior for bias up to the built-in voltage. By employing the 1N4007 diode as a case study, we analyzed the impedance over a wide frequency range, from 1 Hz to 1 MHz. Our analysis reveals that impedance can be effectively studied by combining two models. In both models, the depletion capacitance is assumed to be an ideal capacitor with a value independent of frequency. One model accounts for diffusion processes, while the other addresses interfacial effects, as well as potential and capacitance distributions across the junction. This approach offers valuable insights into the complex capacitance behavior of pn junctions as a function of the bias voltage. Measurements of depletion and diffusion capacitances, as well as of the diode transit time can be achieved from a set of impedance spectroscopy data.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"215 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The unreacted equation of state (EOS) for an unreacted explosive can provide fundamental information to understand any analytical model for the shock and initiation process. Based on the Hugoniot expression in Jones–Wilkins–Lee (JWL) form derived from the Mie–Grüneisen EOS and conservation equation across the shock wave, a three-point calibrating method to determine the JWL EOS parameters for unreacted explosives was developed using intelligent algorithms and shock Hugoniot relationship of the explosives considered. The calibration method proposed utilizes the back propagation neural network to predict the nonlinear system composed of different JWL parameter sets; the genetic algorithm is then used to find the optimal solution of the JWL parameter set. Unreacted JWL EOS parameters of eight typical explosives were calibrated using the calibrating method developed, and an excellent agreement can be observed between JWL EOS and experimental p–v curves for all eight explosives selected, indicating the high accuracy of the three-point calibrating method. However, the effectiveness of the three-point calibrating method was experimentally validated with the experimental data measured from the shock tests of the dihydroxylammonium 5,5′-bitetrazole-1,1′-dioxide (TKX-50)-based explosive, where the JWL p–v curve derived from the three-point calibrating method is in good agreement with the experimental curve.
未反应炸药的未反应状态方程（EOS）可为理解冲击和起爆过程的任何分析模型提供基本信息。根据从 Mie-Grüneisen EOS 和整个冲击波守恒方程导出的琼斯-威尔金斯-李（JWL）形式的休伊特表达式，利用智能算法和所考虑的爆炸物的冲击休伊特关系，开发了一种三点校准方法，以确定未反应爆炸物的 JWL EOS 参数。所提出的校准方法利用反向传播神经网络预测由不同 JWL 参数集组成的非线性系统，然后利用遗传算法找到 JWL 参数集的最优解。利用所开发的校准方法对八种典型炸药的未反应 JWL EOS 参数进行了校准，结果表明所选八种炸药的 JWL EOS 与实验 p-v 曲线之间具有极好的一致性，表明三点校准法具有很高的准确性。不过，三点校准法的有效性要通过实验验证，实验数据来自 5,5′-二羟基四唑-1,1′-二氧化物（TKX-50）基二羟基铵炸药的冲击试验，三点校准法得出的 JWL p-v 曲线与实验曲线吻合良好。
{"title":"Calibration of Jones–Wilkins–Lee equation of state for unreacted explosives with shock Hugoniot relationship and optimization algorithm","authors":"Hao Cui, Junan Wu, Yuxin Xu, Hao Zhou, Rui Guo","doi":"10.1063/5.0230362","DOIUrl":"https://doi.org/10.1063/5.0230362","url":null,"abstract":"The unreacted equation of state (EOS) for an unreacted explosive can provide fundamental information to understand any analytical model for the shock and initiation process. Based on the Hugoniot expression in Jones–Wilkins–Lee (JWL) form derived from the Mie–Grüneisen EOS and conservation equation across the shock wave, a three-point calibrating method to determine the JWL EOS parameters for unreacted explosives was developed using intelligent algorithms and shock Hugoniot relationship of the explosives considered. The calibration method proposed utilizes the back propagation neural network to predict the nonlinear system composed of different JWL parameter sets; the genetic algorithm is then used to find the optimal solution of the JWL parameter set. Unreacted JWL EOS parameters of eight typical explosives were calibrated using the calibrating method developed, and an excellent agreement can be observed between JWL EOS and experimental p–v curves for all eight explosives selected, indicating the high accuracy of the three-point calibrating method. However, the effectiveness of the three-point calibrating method was experimentally validated with the experimental data measured from the shock tests of the dihydroxylammonium 5,5′-bitetrazole-1,1′-dioxide (TKX-50)-based explosive, where the JWL p–v curve derived from the three-point calibrating method is in good agreement with the experimental curve.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"17 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. B. Ball, R. J. Husband, J. D. McHardy, M. I. McMahon, C. Strohm, Z. Konôpková, K. Appel, V. Cerantola, A. L. Coleman, H. Cynn, A. Dwivedi, A. F. Goncharov, H. Graafsma, L. Q. Huston, H. Hwang, J. Kaa, J.-Y. Kim, E. Koemets, T. Laurus, X. Li, H. Marquardt, A. S. J. Méndez, S. Merkel, A. Mondal, G. Morard, V. B. Prakapenka, C. Prescher, T. R. Preston, S. Speziale, S. Stern, B. T. Sturtevant, J. Sztuk-Dambietz, N. Velisavljevic, C.-S. Yoo, U. Zastrau, Zs. Jenei, H. P. Liermann, R. S. McWilliams
X-ray self-heating is a common by-product of X-ray Free Electron Laser (XFEL) techniques that can affect targets, optics, and other irradiated materials. Diagnosis of heating and induced changes in samples may be performed using the x-ray beam itself as a probe. However, the relationship between conditions created by and inferred from x-ray irradiation is unclear and may be highly dependent on the material system under consideration. Here, we report on a simple case study of a titanium foil irradiated, heated, and probed by a MHz XFEL pulse train at 18.1 keV delivered by the European XFEL using measured x-ray diffraction to determine temperature and finite element analysis to interpret the experimental data. We find a complex relationship between apparent temperatures and sample temperature distributions that must be accounted for to adequately interpret the data, including beam averaging effects, multivalued temperatures due to sample phase transitions, and jumps and gaps in the observable temperature near phase transformations. The results have implications for studies employing x-ray probing of systems with large temperature gradients, particularly where these gradients are produced by the beam itself. Finally, this study shows the potential complexity of studying nonlinear sample behavior, such as phase transformations, where biasing effects of temperature gradients can become paramount, precluding clear observation of true transformation conditions.
X 射线自热是 X 射线自由电子激光（XFEL）技术的常见副产品，会影响目标、光学器件和其他辐照材料。可以使用 X 射线束本身作为探针，对样品中的加热和诱导变化进行诊断。然而，X 射线辐照所产生的条件与推断出的条件之间的关系尚不明确，而且可能在很大程度上取决于所考虑的材料系统。在此，我们报告了一个简单的案例研究，即欧洲 XFEL 发射的 18.1 千伏的 MHz XFEL 脉冲串对钛箔进行辐照、加热和探测，利用测量的 X 射线衍射确定温度，并利用有限元分析解释实验数据。我们发现表观温度和样品温度分布之间存在复杂的关系，必须考虑到这些因素才能充分解释数据，包括光束平均效应、样品相变引起的多值温度以及相变附近可观测温度的跳跃和间隙。这些结果对采用 X 射线探测具有较大温度梯度的系统的研究具有重要意义，特别是当这些梯度是由光束本身产生的时候。最后，这项研究显示了研究非线性样品行为（如相变）的潜在复杂性，在这种情况下，温度梯度的偏差效应可能变得至关重要，从而阻碍了对真实转变条件的清晰观测。
{"title":"Measurement bias in self-heating x-ray free electron laser experiments from diffraction studies of phase transformation in titanium","authors":"O. B. Ball, R. J. Husband, J. D. McHardy, M. I. McMahon, C. Strohm, Z. Konôpková, K. Appel, V. Cerantola, A. L. Coleman, H. Cynn, A. Dwivedi, A. F. Goncharov, H. Graafsma, L. Q. Huston, H. Hwang, J. Kaa, J.-Y. Kim, E. Koemets, T. Laurus, X. Li, H. Marquardt, A. S. J. Méndez, S. Merkel, A. Mondal, G. Morard, V. B. Prakapenka, C. Prescher, T. R. Preston, S. Speziale, S. Stern, B. T. Sturtevant, J. Sztuk-Dambietz, N. Velisavljevic, C.-S. Yoo, U. Zastrau, Zs. Jenei, H. P. Liermann, R. S. McWilliams","doi":"10.1063/5.0215908","DOIUrl":"https://doi.org/10.1063/5.0215908","url":null,"abstract":"X-ray self-heating is a common by-product of X-ray Free Electron Laser (XFEL) techniques that can affect targets, optics, and other irradiated materials. Diagnosis of heating and induced changes in samples may be performed using the x-ray beam itself as a probe. However, the relationship between conditions created by and inferred from x-ray irradiation is unclear and may be highly dependent on the material system under consideration. Here, we report on a simple case study of a titanium foil irradiated, heated, and probed by a MHz XFEL pulse train at 18.1 keV delivered by the European XFEL using measured x-ray diffraction to determine temperature and finite element analysis to interpret the experimental data. We find a complex relationship between apparent temperatures and sample temperature distributions that must be accounted for to adequately interpret the data, including beam averaging effects, multivalued temperatures due to sample phase transitions, and jumps and gaps in the observable temperature near phase transformations. The results have implications for studies employing x-ray probing of systems with large temperature gradients, particularly where these gradients are produced by the beam itself. Finally, this study shows the potential complexity of studying nonlinear sample behavior, such as phase transformations, where biasing effects of temperature gradients can become paramount, precluding clear observation of true transformation conditions.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"29 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the most important issues related to the strength of metals is the strain rate sensitivity of the flow stress. In this study, an analytical model of the flow stress as a function of strain rate is derived theoretically. The model can reproduce the strain rate sensitivity of the flow stress of copper over a wide range of strain rates (up to 109 s−1) quantitatively. Our theoretical derivations indicate that the strain rate sensitivity of the flow stress, especially that above 103 s−1, is a result of both the variation of the dislocation mobility mechanism with stress and the particular stress dependence of dislocation density but is not a result of each single mechanism. In particular, the stress dependence of the dislocation density and the initial dislocation density are critical to the quantitative relation of the flow stress–strain rate at high strain rate and the strain rate threshold, under which the upturn of the flow stress occurs, respectively. Moreover, experiments with copper of different initial dislocation densities at moderate and high strain rate are performed. The strain rate threshold of the flow stress upturn observed in the experiments grows considerably as initial dislocation density increases, which is in accordance with theoretical prediction by our model.
{"title":"Revisiting the strain rate sensitivity of the flow stress of copper: Theory and experiment","authors":"Songlin Yao, Jidong Yu, Xiaoyang Pei, Kai Guo, Enling Tang, Guiji Wang, Qiang Wu","doi":"10.1063/5.0225090","DOIUrl":"https://doi.org/10.1063/5.0225090","url":null,"abstract":"One of the most important issues related to the strength of metals is the strain rate sensitivity of the flow stress. In this study, an analytical model of the flow stress as a function of strain rate is derived theoretically. The model can reproduce the strain rate sensitivity of the flow stress of copper over a wide range of strain rates (up to 109 s−1) quantitatively. Our theoretical derivations indicate that the strain rate sensitivity of the flow stress, especially that above 103 s−1, is a result of both the variation of the dislocation mobility mechanism with stress and the particular stress dependence of dislocation density but is not a result of each single mechanism. In particular, the stress dependence of the dislocation density and the initial dislocation density are critical to the quantitative relation of the flow stress–strain rate at high strain rate and the strain rate threshold, under which the upturn of the flow stress occurs, respectively. Moreover, experiments with copper of different initial dislocation densities at moderate and high strain rate are performed. The strain rate threshold of the flow stress upturn observed in the experiments grows considerably as initial dislocation density increases, which is in accordance with theoretical prediction by our model.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"1 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. E. García Redondo, N. A. Müller, J. M. Salum, L. P. Ferreyro, J. D. Bonilla-Neira, J. M. Geria, J. J. Bonaparte, T. Muscheid, R. Gartmann, A. Almela, M. R. Hampel, A. E. Fuster, L. E. Ardila-Perez, M. Wegner, M. Platino, O. Sander, S. Kempf, M. Weber
The Microwave SQUID Multiplexer (μMUX) is the device of choice for the readout of a large number of low-temperature detectors in a wide variety of experiments within the fields of astronomy and particle physics. While it offers large multiplexing factors, the system noise performance is highly dependent on the cold- and warm-readout electronic systems used to read it out, as well as the demodulation domain and parameters chosen. In order to understand the impact of the readout systems in the overall detection system noise performance, first, we extended the available μMUX simulation frameworks, including additive and multiplicative noise sources in the probing tones (i.e., phase and amplitude noise), along with the capability of demodulating the scientific data, either in the resonator’s phase or the scattering amplitude. Then, considering the additive noise as a dominant noise source, the optimum readout parameters to achieve minimum system noise were found for both open-loop and flux-ramp demodulation schemes in the aforementioned domains. Later, we evaluated the system noise sensitivity to multiplicative noise sources under the optimum readout parameters. Finally, as a case study, we evaluated the optimal demodulation domain and the expected system noise level for a typical software-defined radio readout system. This work leads to an improved system performance prediction and noise engineering based on the available readout electronics and the selected demodulation domain.
{"title":"Optimal demodulation domain for microwave SQUID multiplexers in presence of readout system noise","authors":"M. E. García Redondo, N. A. Müller, J. M. Salum, L. P. Ferreyro, J. D. Bonilla-Neira, J. M. Geria, J. J. Bonaparte, T. Muscheid, R. Gartmann, A. Almela, M. R. Hampel, A. E. Fuster, L. E. Ardila-Perez, M. Wegner, M. Platino, O. Sander, S. Kempf, M. Weber","doi":"10.1063/5.0222656","DOIUrl":"https://doi.org/10.1063/5.0222656","url":null,"abstract":"The Microwave SQUID Multiplexer (μMUX) is the device of choice for the readout of a large number of low-temperature detectors in a wide variety of experiments within the fields of astronomy and particle physics. While it offers large multiplexing factors, the system noise performance is highly dependent on the cold- and warm-readout electronic systems used to read it out, as well as the demodulation domain and parameters chosen. In order to understand the impact of the readout systems in the overall detection system noise performance, first, we extended the available μMUX simulation frameworks, including additive and multiplicative noise sources in the probing tones (i.e., phase and amplitude noise), along with the capability of demodulating the scientific data, either in the resonator’s phase or the scattering amplitude. Then, considering the additive noise as a dominant noise source, the optimum readout parameters to achieve minimum system noise were found for both open-loop and flux-ramp demodulation schemes in the aforementioned domains. Later, we evaluated the system noise sensitivity to multiplicative noise sources under the optimum readout parameters. Finally, as a case study, we evaluated the optimal demodulation domain and the expected system noise level for a typical software-defined radio readout system. This work leads to an improved system performance prediction and noise engineering based on the available readout electronics and the selected demodulation domain.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":"62 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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