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Author Correction: Local negative permittivity and topological phase transition in polar skyrmions. NATURE MATERIALS 2021; 20:905. [PMID: 33627832 DOI: 10.1038/s41563-021-00962-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
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Engineering new limits to magnetostriction through metastability in iron-gallium alloys. Nat Commun 2021; 12:2757. [PMID: 33980848 PMCID: PMC8115637 DOI: 10.1038/s41467-021-22793-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/30/2021] [Indexed: 11/09/2022] Open
Abstract
Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe1-xGax alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe1-xGax alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe1-xGax - [Pb(Mg1/3Nb2/3)O3]0.7-[PbTiO3]0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10-5 s m-1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.
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Local negative permittivity and topological phase transition in polar skyrmions. NATURE MATERIALS 2021; 20:194-201. [PMID: 33046856 DOI: 10.1038/s41563-020-00818-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 09/01/2020] [Indexed: 06/11/2023]
Abstract
Topological solitons such as magnetic skyrmions have drawn attention as stable quasi-particle-like objects. The recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened up new vistas to explore topology, emergent phenomena and approaches for manipulating such features with electric fields. Using macroscopic dielectric measurements, coupled with direct scanning convergent beam electron diffraction imaging on the atomic scale, theoretical phase-field simulations and second-principles calculations, we demonstrate that polar skyrmions in (PbTiO3)n/(SrTiO3)n superlattices are distinguished by a sheath of negative permittivity at the periphery of each skyrmion. This enhances the effective dielectric permittivity compared with the individual SrTiO3 and PbTiO3 layers. Moreover, the response of these topologically protected structures to electric field and temperature shows a reversible phase transition from the skyrmion state to a trivial uniform ferroelectric state, accompanied by large tunability of the dielectric permittivity. Pulsed switching measurements show a time-dependent evolution and recovery of the skyrmion state (and macroscopic dielectric response). The interrelationship between topological and dielectric properties presents an opportunity to simultaneously manipulate both by a single, and easily controlled, stimulus, the applied electric field.
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Inflamed Mind: Multiple Genetic Variants of IL6 Influence Suicide Risk Phenotypes in Interaction With Early and Recent Adversities in a Linkage Disequilibrium-Based Clumping Analysis. Front Psychiatry 2021; 12:746206. [PMID: 34777050 PMCID: PMC8585756 DOI: 10.3389/fpsyt.2021.746206] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Understanding and predicting suicide remains a challenge, and a recent paradigm shift regarding the complex relationship between the immune system and the brain brought attention to the involvement of inflammation in neuropsychiatric conditions including suicide. Among cytokines, IL-6 has been most frequently implicated in suicide, yet only a few candidate gene studies and without considering the effect of stress investigated the role of IL6 in suicidal behaviour. Our study aimed to investigate the association of IL6 variation with a linkage disequilibrium-based clumping method in interaction with childhood adversities and recent stress on manifestations along the suicide spectrum. Methods: One thousand seven hundred and sixty-two participants provided information on previous suicide attempts, current suicidal ideation, thoughts of death, and hopelessness, and were genotyped for 186 variants in IL6. Early childhood adversities were recorded with an instrument adapted from the Childhood Trauma Questionnaire, recent life events were registered using the List of Threatening Life Events. Following a 3-step quality control, logistic and linear regression models were run to explore the effect of genotype and gene-environment interactions on suicide phenotypes. All regression models were followed by a clumping process based on empirical estimates of linkage disequilibrium between clumps of intercorrelated SNPs. Interaction effects of distinct types of recent life events were also analysed. Results: No clumps with significant main effects emerged, but we identified several clumps significantly interacting with childhood adversities on lifetime suicide attempts, current suicidal ideation, and current thoughts of death. We also identified clumps significantly interacting with recent negative life events on current suicidal ideation. We reported no clumps with significant effect on hopelessness either as a main effect or in interaction with childhood adversities or recent stress. Conclusion: We identified variant clumps in IL6 influencing suicidal behaviour, but only in interaction with childhood or recent adversities. Our results may bring us a step further in understanding the role of neuroinflammation and specifically of IL-6 in suicide, towards identifying novel biological markers of suicidal behaviour especially in those exposed to stressful experiences, and to fostering the adaptation of a new paradigm and identifying novel approaches and targets in the treatment of suicidal behaviour.
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Tunable Magnetoelastic Effects in Voltage-Controlled Exchange-Coupled Composite Multiferroic Microstructures. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6752-6760. [PMID: 31927947 DOI: 10.1021/acsami.9b20876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The magnetoelectric properties of exchange-coupled Ni/CoFeB-based composite multiferroic microstructures are investigated. The strength and sign of the magnetoelastic effect are found to be strongly correlated with the ratio between the thicknesses of two magnetostrictive materials. In cases where the thickness ratio deviates significantly from one, the magnetoelastic behavior of the multiferroic microstructures is dominated by the thicker layer, which contributes more strongly to the observed magnetoelastic effect. More symmetric structures with a thickness ratio equal to one show an emergent interfacial behavior which cannot be accounted for simply by summing up the magnetoelastic effects occurring in the two constituent layers. This aspect is clearly visible in the case of ultrathin bilayers, where the exchange coupling drastically affects the magnetic behavior of the Ni layer, making the Ni/CoFeB bilayer a promising next-generation synthetic magnetic system entirely. This study demonstrates the richness and high tunability of composite multiferroic systems based on coupled magnetic bilayers compared to their single magnetic layer counterparts. Furthermore, because of the compatibility of CoFeB with present magnetic tunnel junction-based spintronic technologies, the reported findings are expected to be of great interest for the development of ultralow-power magnetoelectric memory devices.
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"Out, out, brief candle! Life's but a walking shadow": 5-HTTLPR Is Associated With Current Suicidal Ideation but Not With Previous Suicide Attempts and Interacts With Recent Relationship Problems. Front Psychiatry 2020; 11:567. [PMID: 32670107 PMCID: PMC7331851 DOI: 10.3389/fpsyt.2020.00567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Suicide is an unresolved psychiatric and public health emergency, claiming 800,000 lives each year, however, its neurobiological etiology is still not understood. In spite of original reports concerning the involvement of 5-HTTLPR in interaction with recent stress in the appearance of suicidal ideation and attempts, replication studies have yielded contradictory results. In our study, we analyzed the association between 5-HTTLPR and lifetime suicide attempts, current suicidal ideation, hopelessness and thoughts of death as main effects, and in interaction with childhood adversities, recent stress, and different types of recent life events in a general population sample. METHODS Two thousand and three hundred fifty-eight unrelated European volunteers were genotyped for 5-HTTLPR, provided phenotypic data on previous suicide attempts, and current suicidal ideation, hopelessness and thoughts about death, and information on childhood adversities and recent life events. Logistic and linear regression models were run with age, gender, and population as covariates to test for the effect of 5-HTTLPR as a main effect and in interaction with childhood adversities and recent life events on previous suicide attempts and current suicidal ideation. Benjamini-Hochberg FDR Q values were calculated to correct for multiple testing. RESULTS 5-HTTLPR had no significant effect on lifetime suicide attempts either as a main effect on in interaction with childhood adversities. 5-HTTLPR had a significant main effect on current suicidal ideation in the dominant model (Q=0.0344). 5-HTTLPR did not interact with childhood adversities or total number of recent life events on any phenotypes related to current suicidal risk, however, a significant interaction effect between 5-HTTLPR and current relationship problems emerged in the case of current suicidal ideation in the dominant model (Q=0.0218) and in the case of thoughts about death and dying in the dominant (Q=0.0094) and additive models (Q=0.0281). CONCLUSION While 5-HTTLPR did not influence previous suicide attempts or interacted with childhood adversities, it did influence current suicidal ideation with, in addition, an interaction with recent relationship problems supporting the involvement of 5-HTTLPR in suicide. Our findings that 5-HTTLPR impacts only certain types of suicide risk-related behaviors and that it interacts with only distinct types of recent stressors provides a possible explanation for previous conflicting findings.
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Time-dependent changes in kidney histopathology in ethylene glycol poisoning. MEDICINE, SCIENCE, AND THE LAW 2018; 58:257-260. [PMID: 30124101 DOI: 10.1177/0025802418795352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ethylene glycol (EG) may be acutely toxic following ingestion. In fatal cases, microscopic examination of urine and kidney specimens can establish a post-mortem diagnosis of EG poisoning. We describe the main renal histopathologic changes during different stages of EG poisoning, which might be helpful when dating the EG poisoning itself. A single-centre retrospective study conducted on all EG poisoning cases demonstrated that in an early stage of EG poisoning, fine dust-like crystals were deposited to the tubular cell basement membrane, followed by internalisation of calcium oxalate crystals into the epithelial cells. Later, the crystals formed larger aggregates within the epithelial cells. As the changes became advanced, pronounced tubular epithelial damage occurred, with detachment of epithelial cells from the basement membrane. In the final stage, coarse calcium oxalate crystals were recognised in the tubular lumen, with cellular debris from damaged epithelial cells. Our study shows that the time-dependent histological changes described follow the clinical stages of EG poisoning and may therefore provide a rough estimate of the time of EG ingestion before death.
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Abstract
This study aimed to establish the number of deaths in infants under 1 year of age that were being reported for medico-legal examination at a single large academic centre in Hungary, as well as the method of these investigations with special emphasis on histopathology, ancillary techniques and the adherence of our current practice to international recommendations. A single-centre, retrospective audit was conducted on all suspected sudden infant death cases. After the review there were eight infectious background sudden infant death syndrome (SIDS) cases, infectious respiratory tract disease in 14 cases, cardiac septal tumour in one case, and hepatic, possibly metabolic, disorder in one case. Our study has highlighted that even in a single institution there is a huge heterogeneity of approaches which needs standardisation. A reclassification of infant cases according to the San Diego definition resulted in a decreased number of SIDS cases in our material. The San Diego definition and related international recommendations were found to be practical and the classification provides a guide to the standardisation of current practice.
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[Association between the 5-HTTLPR polymorphism of the serotonin transporter gene and suicide: a case-control pilot study]. NEUROPSYCHOPHARMACOLOGIA HUNGARICA : A MAGYAR PSZICHOFARMAKOLOGIAI EGYESULET LAPJA = OFFICIAL JOURNAL OF THE HUNGARIAN ASSOCIATION OF PSYCHOPHARMACOLOGY 2017; 19:5-10. [PMID: 28467954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVES Besides psychological and social effects, biological, biochemical and genetic factors also play a role in the background of suicide. The aim is developing a complex model incorporating all the above factors so that suicide could be predicted and prevented in those at risk. Based on several studies 5-HTTLPR s allele frequency is increased in case of violent completed suicides. The aim of the present study was to validate this association in a sample of completed suicides. METHODS During autopsy sample DNA samples were obtained for 5-HTTLPR genotyping from 200 subjects deceased due to suicide and 200 controls deceased due to other causes. Chi square tests and logistic regressions were performed according to additive, dominant and recessive models to analyse the possible association between 5-HTTLPR genotype distribution and suicide. RESULTS Ratio of violent and non-violent suicides was 81% and 19% respectively. No significant difference was found in the distribution of 5-HTTLPR genotypes between the suicide and controls samples. No difference was found between violent and nonviolent suicides with respect to genotype distribution. A significant association was found between sl genotype and suicide at a younger age. CONCLUSIONS Our pilot study did not support the supposed association between 5-HTTLPR and completed suicides or with violent completed suicides. However we found a significant association between sl genotype and suicide in young suicidals.
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MoS2 transistors with 1-nanometer gate lengths. Science 2016; 354:99-102. [DOI: 10.1126/science.aah4698] [Citation(s) in RCA: 873] [Impact Index Per Article: 109.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/07/2016] [Indexed: 01/19/2023]
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All-electrical nuclear spin polarization of donors in silicon. PHYSICAL REVIEW LETTERS 2013; 110:057601. [PMID: 23414045 DOI: 10.1103/physrevlett.110.057601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate an all-electrical donor nuclear spin polarization method in silicon by exploiting the tunable interaction of donor bound electrons with a two-dimensional electron gas, and achieve over two orders of magnitude nuclear hyperpolarization at T=5 K and B=12 T with an in-plane magnetic field. We also show an intricate dependence of nuclear polarization effects on the orientation of the magnetic field, and both hyperpolarization and antipolarization can be controllably achieved in the quantum Hall regime. Our results demonstrate that donor nuclear spin qubits can be initialized through local gate control of electrical currents without the need for optical excitation, enabling the implementation of nuclear spin qubit initialization in dense multiqubit arrays.
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Mapping Local Charge Recombination Heterogeneity by Multidimensional Nanospectroscopic Imaging. Science 2012; 338:1317-21. [DOI: 10.1126/science.1227977] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Electrically detected magnetic resonance of neutral donors interacting with a two-dimensional electron gas. PHYSICAL REVIEW LETTERS 2011; 106:207601. [PMID: 21668263 DOI: 10.1103/physrevlett.106.207601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Indexed: 05/30/2023]
Abstract
We have measured the electrically detected magnetic resonance of donor-doped silicon field-effect transistors in resonant X- (9.7 GHz) and W-band (94 GHz) microwave cavities. The two-dimensional electron gas resonance signal increases by 2 orders of magnitude from X to W band, while the donor resonance signals are enhanced by over 1 order of magnitude. Bolometric effects and spin-dependent scattering are inconsistent with the observations. We propose that polarization transfer from the donor to the two-dimensional electron gas is the main mechanism giving rise to the spin resonance signals.
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Electrically detected magnetic resonance in a W-band microwave cavity. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:034704. [PMID: 21456773 DOI: 10.1063/1.3557395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe a low-temperature sample probe for the electrical detection of magnetic resonance in a resonant W-band (94 GHz) microwave cavity. The advantages of this approach are demonstrated by experiments on silicon field-effect transistors. A comparison with conventional low-frequency measurements at X-band (9.7 GHz) on the same devices reveals an up to 100-fold enhancement of the signal intensity. In addition, resonance lines that are unresolved at X-band are clearly separated in the W-band measurements. Electrically detected magnetic resonance at high magnetic fields and high microwave frequencies is therefore a very sensitive technique for studying electron spins with an enhanced spectral resolution and sensitivity.
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Relation Between Temperature and Solidification Velocity in
Rapidly Cooled Liquid Silicon. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-35-181] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTA semi-empirical method to determine the undercooling-velocity relationship
for laser induced melting is presented. The technique uses measurements of
melt depth versus time to control numerical simulations, resulting in a map
of the interface temperature as a function of time, and consequently as a
function of the interface velocity. The results are independent of any model
for the velocity-undercooling relationship. Results of the technique on
simulated and experimental melt depth data are presented. Transient
conductance data on 28 nanosecond 694 nm laser irradiation of silicon
indicate an undercooling-velocity slope of 17±3 K/(m/sec) near the melting
point. Picosecond optical transmission data show a much smaller slope.
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Chemical Raman enhancement of organic adsorbates on metal surfaces. PHYSICAL REVIEW LETTERS 2011; 106:083003. [PMID: 21405569 DOI: 10.1103/physrevlett.106.083003] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Indexed: 05/16/2023]
Abstract
Using first-principles theory and experiments, chemical contributions to surface-enhanced Raman spectroscopy for a well-studied organic molecule, benzene thiol, chemisorbed on planar Au(111) surfaces are explained and quantified. Density functional theory calculations of the static Raman tensor demonstrate a strong mode-dependent modification of benzene thiol Raman spectra by Au substrates. Raman active modes with the largest enhancements result from stronger contributions from Au to their electron-vibron coupling, as quantified through a deformation potential. A straightforward and general analysis is introduced to extract chemical enhancement from experiments for specific vibrational modes; measured values are in excellent agreement with our calculations.
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Switching a magnetic vortex by interlayer coupling in epitaxially grown Co/Cu/Py/Cu(001) trilayer disks. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:342001. [PMID: 21403243 DOI: 10.1088/0953-8984/22/34/342001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Epitaxial Py/Cu/Co/Cu(001) trilayers were patterned into micron sized disks and imaged using element-specific photoemission electron microscopy. By varying the Cu spacer layer thickness, we study how the coupling between the two magnetic layers influences the formation of magnetic vortex states. We find that while the Py and Co disks form magnetic vortex domains when the interlayer coupling is ferromagnetic, the magnetic vortex domains of the Py and Co disks break into anti-parallel aligned multidomains when the interlayer coupling is antiferromagnetic. We explain this result in terms of magnetic flux closure between the Py and Co layers for the antiferromagnetic coupling case.
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Fabrication of Dense Arrays of Platinum Nanowires on Silica, Alumina, Zirconia and Ceria Surfaces as 2-D Model Catalysts. Catal Letters 2005. [DOI: 10.1007/s10562-005-8681-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demonstrated in a vacuum chamber coupled to the ion beam line. Dot arrays are formed by ion implantation in resist layers on silicon samples with dot diameters limited by the hole size in the probe tips of a few hundred nm.
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Fabrication of large number density platinum nanowire arrays by size reduction lithography and nanoimprint lithography. NANO LETTERS 2005; 5:745-8. [PMID: 15826120 DOI: 10.1021/nl050228q] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Large number density Pt nanowires with typical dimensions of 12 microm x 20 nm x 5 nm (length x width x height) are fabricated on planar oxide supports. First sub-20 nm single crystalline silicon nanowires are fabricated by size reduction lithography, and then the Si nanowire pattern is replicated to produce a large number of Pt nanowires by nanoimprint lithography. The width and height of the Pt nanowires are uniform and are controlled with nanometer precision. The nanowire number density is 4 x 10(4) cm(-1), resulting in a Pt surface area larger than 2 cm(2) on a 5 x 5 cm(2) oxide substrate. Bimodal nanowires with different width have been generated by using a Pt shadow deposition technique. Using this technique, alternating 10 and 19 nm wide nanowires are produced.
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Abstract
A new phase-shifting interferometry analysis technique has been developed to overcome the errors introduced by nonlinear, irregular, or unknown phase-step increments. In the presence of a spatial carrier frequency, by observation of the phase of the first-order maximum in the Fourier domain, the global phase-step positions can be measured, phase-shifting elements can be calibrated, and the accuracy of phase-shifting analysis can be improved. Furthermore, reliance on the calibration accuracy of transducers used in phase-shifting interferometry can be reduced; and phase-retrieval errors (e.g., fringe print-through) introduced by uncalibrated fluctuations in the phase-shifting phase increments can be alleviated. The method operates deterministically and does not rely on iterative global error minimization. Relative to other techniques, the number of recorded interferograms required for analysis can be reduced.
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Abstract
We demonstrate 100-nm-resolution holographic aerial image monitoring based on lensless Fourier-transform holography at extreme-UV (EUV) wavelengths, using synchrotron-based illumination. This method can be used to monitor the coherent imaging performance of EUV lithographic optical systems. The system has been implemented in the EUV phase-shifting point-diffraction interferometer recently developed at Lawrence Berkeley National Laboratory. Here we introduce the idea of the holographic aerial image-recording technique and present imaging performance characterization results for a 10x Schwarzschild objective, a prototype EUV lithographic optic. The results are compared with simulations, and good agreement is obtained. Various object patterns, including phase-shift-enhanced patterns, have been studied. Finally, the application of the holographic aerial image-recording technique to EUV multilayer mask-blank defect characterization is discussed.
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Transmission phase gratings for EUV interferometry. JOURNAL OF SYNCHROTRON RADIATION 2000; 7:405-10. [PMID: 16609228 DOI: 10.1107/s0909049500010670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2000] [Accepted: 07/28/2000] [Indexed: 05/08/2023]
Abstract
The performance of the recently developed EUV phase-shifting point diffraction interferometer (PS/PDI) depends heavily on the characteristics of the grating beamsplitter used in the implementation. Ideally, such a grating should provide throughput of better than 25% and diffraction efficiency, defined as the ratio of the first-diffracted-order power to the zero-order power, variable in the range from approximately 10 to 500. The optimal method for achieving these goals is by way of a phase grating. Also, PS/PDI system implementation issues favor the use of transmission gratings over reflection gratings. Here, the design, fabrication, and characterization of a recently developed transmission phase grating developed for use in EUV interferometry is described.
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At-wavelength, system-level flare characterization of extreme-ultraviolet optical systems. APPLIED OPTICS 2000; 39:2941-2947. [PMID: 18345220 DOI: 10.1364/ao.39.002941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The extreme-ultraviolet (EUV) phase-shifting point-diffraction interferometer (PS/PDI) has recently been developed to provide high-accuracy wave-front characterization critical to the development of EUV lithography systems. Here we describe an enhanced implementation of the PS/PDI that significantly extends its measurement bandwidth. The enhanced PS/PDI is capable of simultaneously characterizing both wave front and flare. PS/PDI-based flare characterization of two recently fabricated EUV 10x-reduction lithographic optical systems is presented.
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Extreme-ultraviolet phase-shifting point-diffraction interferometer: a wave-front metrology tool with subangstrom reference-wave accuracy. APPLIED OPTICS 1999; 38:7252-7263. [PMID: 18324274 DOI: 10.1364/ao.38.007252] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The phase-shifting point-diffraction interferometer (PS/PDI) was recently developed and implemented at Lawrence Berkeley National Laboratory to characterize extreme-ultraviolet (EUV) projection optical systems for lithography. Here we quantitatively characterize the accuracy and precision of the PS/PDI. Experimental measurements are compared with theoretical results. Two major classes of errors affect the accuracy of the interferometer: systematic effects arising from measurement geometry and systematic and random errors due to an imperfect reference wave. To characterize these effects, and hence to calibrate the interferometer, a null test is used. This null test also serves as a measure of the accuracy of the interferometer. We show the EUV PS/PDI, as currently implemented, to have a systematic error-limited reference-wave accuracy of 0.0028 waves (lambda/357 or 0.038 nm at lambda = 13.5 nm) within a numerical aperture of 0.082.
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Phase effects owing to multilayer coatings in a two-mirror extreme-ultraviolet schwarzschild objective. APPLIED OPTICS 1998; 37:8021-8029. [PMID: 18301694 DOI: 10.1364/ao.37.008021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The aberrations of a multilayer-coated reflective Schwarzschild objective, which are influenced both by mirror surface profiles and by multilayer coatings, are evaluated with a phase-shifting point diffraction interferometer operating in the extreme ultraviolet. Using wave-front measurements at multiple wavelengths near 13.4 nm, we observed chromatic aberrations and wavelength-dependent transmission changes that were due to molybdenum-silicon multilayer coatings. The effects of chromatic vignetting due to limited multilayer reflection passbands on the imaging performance of the Schwarzschild optic are considered. The coating characteristics extracted from the interferometry data on the two-mirror optical system are compared with previously reported coating properties measured on individual mirror substrates.
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Near-field propagation of terahertz pulses from a large-aperture antenna. OPTICS LETTERS 1998; 23:213-215. [PMID: 18084463 DOI: 10.1364/ol.23.000213] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The near-field propagation behavior of terahertz (THz) pulses generated by a planar large-aperture photoconducting THz transmitter has been characterized. A simulation model based on Huygens-Fresnel diffraction theory has been developed that permits accurate prediction of the spatiotemporal profiles of the THz beam everywhere and gives excellent agreement with experimental measurements. Two key conclusions emerge from this research, namely, the realization that for practical laboratory setups one is always working in the near-field regime and that the proper temporal shape of the THz field at the antenna is one that rises rapidly but decays slowly.
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Ultrafast carrier dynamics on the Si(100)2 x 1 surface. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R17300-R17303. [PMID: 9985942 DOI: 10.1103/physrevb.54.r17300] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Abstract
We describe a novel interferometer design suitable for highly accurate measurement of wave-front aberrations over a wide range of wavelengths, from visible to x ray. The new design, based on the point diffraction interferometer, preserves the advantages of the conventional point diffraction interferometer but offers higher efficiency and improved accuracy through phase shifting. These qualities make it applicable to at-wavelength testing of many optical systems, including short-wavelength projection lithography optics. A visible-light prototype was built and operated.
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Undulator radiation for at-wavelength interferometry of optics for extreme-ultraviolet lithography. APPLIED OPTICS 1993; 32:7022-7031. [PMID: 20856562 DOI: 10.1364/ao.32.007022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Techniques are described for at-wavelength interferometry of multilayer coated optics designed for use in extreme-ultraviolet lithography. Broadly tunable undulator radiation, which covers the spectral region from 45 to 400 A, is described. The coherent power available at these wavelengths is described, and several types of interferometer that might be suitable at these short wavelengths are also described.
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Abstract
A molybdenum/silicon multilayer-coated 1:1 ring-field optic with a numerical aperture of 0.0835 is used to carry out soft-x-ray projection imaging with undulator radiation at 12.9 nm. An ideal optic of this type should be able to image 0.1-µm features with a contrast exceeding 90% at this wavelength. The useful resolution of our ring-field optic is experimentally found to be approximately 0.2 µm, probably because of the presence of substrate figuring errors.
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Soft-x-ray projection lithography experiments using Schwarzschild imaging optics. APPLIED OPTICS 1993; 32:7068-7071. [PMID: 20856569 DOI: 10.1364/ao.32.007068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Soft-x-ray projection imaging is demonstrated by the use of 14-nm radiation from a laser plasma source and a single-surface multilayer-coated ellipsoidal condenser. Aberrations in the condenser and the Schwarzschild imaging objective are characterized and correlated with imaging performance. A new Schwarzschild housing, designed for improved alignment stability, is described.
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Modeling Time Varying System Perturbations: Application to Robust Change Detection and Identification. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s1474-6670(17)48320-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Observation of above-threshold multiphoton photoelectric emission from image-potential surface states. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:10980-10982. [PMID: 9999141 DOI: 10.1103/physrevb.44.10980] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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Diffraction-limited soft-x-ray projection imaging using a laser plasma source. OPTICS LETTERS 1991; 16:1557-1559. [PMID: 19777030 DOI: 10.1364/ol.16.001557] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Projection imaging of 0.1-microm lines and spaces is demonstrated with a Mo/Si multilayer coated Schwarzschild objective and 14-nm illumination from a laser plasma source. This structure has been etched into a silicon wafer by using a trilevel resist and reactive ion etching. Low-contrast modulation at 0.05-microm lines and spaces is observed in polymethylmethacrylate.
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[Atypical lumbar and nerve-root pain associated with the HTLV-1 virus]. REVUE DU RHUMATISME ET DES MALADIES OSTEO-ARTICULAIRES 1990; 57:869-72. [PMID: 2150450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The human retrovirus HTLV-1 (Human T-cell Lymphotrophic Virus) is responsible for malignant proliferations of mature T lymphocytes. It is also now implicated in neurological disorders dominated by spastic paraplegia. A study of 140 cases of lumbar and root pain enabled us to identify 8 of apparently idiopathic atypical lumbar and root pain which led to the discovery of a positive HTLV-1 serology performed routinely. These cases were remarkable in terms of the rarity and minimal extent of spinal cord signs and of Lasegue's sign, their duration of more than a year and the existence of neurological signs indicative of central involvement. In 2 patients there was secondary progression to a spastic paraparesis. It would appear that the neurotropism of HTLV-1 virus is not limited to the central nervous system but that it can also involve the peripheral nervous system as indicated by certain cases in the literature as well as those collected in Martinique, an endemic area for the virus. Rheumatologists should be aware of this possibility when confronted with such cases of atypical lumbar and root pain and should seek the existence of an HTLV-1 virus infection among other viral etiologies, in particular when the patient concerned comes from an endemic area.
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Abstract
A variety of important dynamical phenomena at metal and semiconductor surfaces are now being investigated with the use of new ultrafast measurement techniques involving lasers and nonlinear optics. Understanding of the rates and mechanisms for relaxation of optical excitations of the surface itself as well as those of adsorbates on the surface is providing new insight into surface chemistry, surface phase transitions, and surface recombination of charge carriers in semiconductors.
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Signal effect analysis for noise diagnostics of a nuclear power plant. PROGRESS IN NUCLEAR ENERGY 1988. [DOI: 10.1016/0149-1970(88)90098-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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An expert system approach to the development of noise diagnostic system in NPP paks. PROGRESS IN NUCLEAR ENERGY 1988. [DOI: 10.1016/0149-1970(88)90038-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Picosecond surface electron dynamics on photoexcited Si(111)(2 x 1) surfacs surfaces. PHYSICAL REVIEW LETTERS 1986; 57:881-884. [PMID: 10034185 DOI: 10.1103/physrevlett.57.881] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Direct observation of adsorbate-induced band-gap states on GaAs(110). PHYSICAL REVIEW LETTERS 1986; 56:2846-2849. [PMID: 10033110 DOI: 10.1103/physrevlett.56.2846] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from patients with spinal cord injury. J Urol 1986; 135:402-8. [PMID: 3944881 DOI: 10.1016/s0022-5347(17)45653-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from spinal cord injury patients with detrusor sphincter dyssynergia were investigated neurochemically and histochemically. Catecholamine fluorescence histochemistry provided no evidence for the presence of adrenergic nerves associated with the skeletal muscle. The noradrenaline content of this region probably reflects the endogenous levels in adrenergic nerves associated with the blood vessels supplying the skeletal muscle. Choline acetyltransferase activity in the skeletal muscle was significantly lower in patients with cervical lesions than in those with thoracic lesions (p less than 0.01). The noradrenaline content of the smooth muscle was significantly lower in cervical lesions than in thoracic lesions in both the mid (p less than 0.02) and the distal (p less than 0.001) regions of the urethra. The proximal region revealed similar noradrenaline levels in both groups of spinal cord injury patients. The results are discussed in relation to the role of the autonomic nervous system in the control of voiding and to the presence of increased sympathetic outflow in patients with spinal cord lesions at higher levels.
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