Pundt, Astrid

[["dc.bibliographiccitation.firstpage","709"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Scripta Materialia"],["dc.bibliographiccitation.lastpage","712"],["dc.bibliographiccitation.volume","62"],["dc.contributor.author","Tal-Gutelmacher, E."],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.author","Kirchheim, Reiner"],["dc.date.accessioned","2018-11-07T08:43:53Z"],["dc.date.available","2018-11-07T08:43:53Z"],["dc.date.issued","2010"],["dc.description.abstract","The effect of residual hydrogen, sorbed during the deposition process, on the hydrogenation behavior of ion-beam sputtered titanium thin films was investigated. Electromotive force and in situ stress measurements were conducted to study hydrogen absorption, phase boundaries and hydrogen-induced stress development in the Ti-H thin film system. Tests were conducted on both as-sputtered and previously discharged films; the effect of residual hydrogen is significantly manifested in the thermodynamic isotherms and stress-concentration curves. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","Alexander von Humboldt foundation"],["dc.identifier.doi","10.1016/j.scriptamat.2010.01.037"],["dc.identifier.isi","000275933700020"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20077"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1359-6462"],["dc.title","The effect of residual hydrogen on hydrogenation behavior of titanium thin films"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","479"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","483"],["dc.bibliographiccitation.volume","446"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Proeger, Till E."],["dc.contributor.author","Danis, Stanislav"],["dc.contributor.author","Cieslar, M."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T10:57:35Z"],["dc.date.available","2018-11-07T10:57:35Z"],["dc.date.issued","2007"],["dc.description.abstract","The introduction of new defects due to H-loading of Nb, their population as a function of the H concentration, and the mechanism of their formation are investigated by positron annihilation spectroscopy (PAS). In addition, X-ray diffraction (XRD), and transmission electron microscopy (TEM) are applied. Furthermore, the results obtained by the experimental techniques are compared with theoretical calculations of energetic stability and positron characteristics of various defect-H configurations. It is found that vacancies surrounded by H atoms are introduced into the specimens by H-loading. The density of these vacancy-H complexes increases with increasing concentration of H in the specimens. The H-induced vacancies are formed even in the alpha-phase field, when the metal-H system is a single phase solid solution. The stability of the H-induced defects and the mechanism of their formation are discussed. (C) 2006 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2006.11.105"],["dc.identifier.isi","000250822900102"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50289"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","10th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications"],["dc.relation.eventlocation","Lahaina, HI"],["dc.relation.issn","0925-8388"],["dc.title","Hydrogen-induced defects in niobium"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","224106"],["dc.bibliographiccitation.issue","22"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","69"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Becvar, F."],["dc.contributor.author","Kuzel, R."],["dc.contributor.author","Cieslar, M."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T10:48:43Z"],["dc.date.available","2018-11-07T10:48:43Z"],["dc.date.issued","2004"],["dc.description.abstract","Our aim in the present work was to investigate changes of the defect structure of bulk niobium induced by hydrogen loading. The evolution of the microstructure with increasing hydrogen concentration was studied by x-ray diffraction and two complementary techniques of positron annihilation spectroscopy (PAS), namely positron lifetime spectroscopy and slow positron implantation spectroscopy with the measurement of Doppler broadening, in defect-free Nb (99.9%) and Nb containing a remarkable number of dislocations. These samples were electrochemically loaded with hydrogen up to x(H)=0.06 [H/Nb], i.e., in the alpha-phase region, and it was found that the defect density increases with hydrogen concentration in both Nb samples. This means that hydrogen-induced defects are created in the Nb samples. A comparison of PAS results with theoretical calculations revealed that vacancy-hydrogen complexes are introduced into the samples due to hydrogen loading. Most probably these are vacancies surrounded by 4 hydrogen atoms."],["dc.identifier.doi","10.1103/PhysRevB.69.224106"],["dc.identifier.isi","000222530900027"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48260"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Hydrogen-induced defects in bulk niobium"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","262"],["dc.bibliographiccitation.journal","Acta Materialia"],["dc.bibliographiccitation.lastpage","267"],["dc.bibliographiccitation.volume","155"],["dc.contributor.author","Martin, May L."],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.author","Kirchheim, Reiner"],["dc.date.accessioned","2020-12-10T14:14:52Z"],["dc.date.available","2020-12-10T14:14:52Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1016/j.actamat.2018.06.011"],["dc.identifier.issn","1359-6454"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/71529"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Hydrogen-induced accelerated grain growth in vanadium"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","241"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Applied Surface Science"],["dc.bibliographiccitation.lastpage","244"],["dc.bibliographiccitation.volume","255"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Vlach, Martin"],["dc.contributor.author","Zaludova, N."],["dc.contributor.author","Danis, Stanislav"],["dc.contributor.author","Dobron, Patrik"],["dc.contributor.author","Chmelik, F."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Muecklich, Arndt"],["dc.contributor.author","Nikitin, E."],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T11:09:48Z"],["dc.date.available","2018-11-07T11:09:48Z"],["dc.date.issued","2008"],["dc.description.abstract","Hydrogen loading of thin films introduces very high compressive stresses which grow in magnitude with increasing hydrogen concentration. When the hydrogen-induced stresses exceed a certain critical in-plane stress value, the loaded film starts to detach from the substrate. This results in the formation of buckles of various morphologies in the film layer. Defect studies of a hydrogen loaded Pd film which undergoes a buckling process are presented, using slow positron implantation spectroscopy, in situ acoustic emission, and direct observations of the film structure by transmission electron and optical microscopies. It is found that buckling of the film occurs at hydrogen concentrations x(H) >= 0.1 and causes a significant increase of the dislocation density in the film. (c) 2008 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.apsusc.2008.05.290"],["dc.identifier.isi","000259726900065"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/53087"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","11th Workshop on Slow Position Beam Techniques for Solids and Surfaces"],["dc.relation.eventlocation","Musee Sci Naturelles, Orleans, FRANCE"],["dc.relation.issn","0169-4332"],["dc.title","Hydrogen-induced buckling of Pd films studied by positron annihilation"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","S872"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","S876"],["dc.bibliographiccitation.volume","509"],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Al-Kassab, Talaat"],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T08:52:06Z"],["dc.date.available","2018-11-07T08:52:06Z"],["dc.date.issued","2011"],["dc.description.abstract","V-Fe5at.% 2 and 10-nm thick single layered films were prepared by ion beam sputtering on W substrate. They were loaded with D from gas phase at 0.2 Pa and at 1 Pa, respectively. Both lateral and depth D distribution of these films was investigated in detail by atom probe tomography. The results of analysis are in good agreement between the average deuterium concentration and the value, expected from electromotive force measurement on a similar flat film. An enrichment of deuterium at the V/W interface was observed for both films. The origin of this D-accumulation was discussed in respect to electron transfer, mechanical stress and misfit dislocations. (C) 2010 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2010.11.122"],["dc.identifier.isi","000295695500081"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22090"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","12th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications (MH2010)"],["dc.relation.eventend","2010-07-23"],["dc.relation.eventlocation","Moscow, Russia"],["dc.relation.eventstart","2010-07-19"],["dc.relation.issn","0925-8388"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Analysis of deuterium in V-Fe5at.% film by atom probe tomography (APT)"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","903"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Scripta Materialia"],["dc.bibliographiccitation.lastpage","906"],["dc.bibliographiccitation.volume","67"],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Al-Kassab, Talaat"],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T09:03:08Z"],["dc.date.available","2018-11-07T09:03:08Z"],["dc.date.issued","2012"],["dc.description.abstract","The first direct observation, by atom probe tomography, of a deuterium dead layer is reported for Fe/V multilayered film loaded with D solute atoms. The thickness of the dead layers was measured to be 0.4-0.5 nm. The dead layers could be distinguished from chemically intermixed layers. The results suggest that the dead layer effect occurs even near the interface of the mixing layers, supporting an interpretation that the dead layer effect cannot be explained solely by electronic charge transfer but also involves a modulation of rigidity. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.scriptamat.2012.08.025"],["dc.identifier.isi","000310390000009"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24840"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1359-6462"],["dc.title","Visualization of deuterium dead layer by atom probe tomography"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","075408"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","64"],["dc.contributor.author","Sachs, C."],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Winter, M."],["dc.contributor.author","Reetz, M. T."],["dc.contributor.author","Fritsch, D."],["dc.date.accessioned","2018-11-07T08:45:50Z"],["dc.date.available","2018-11-07T08:45:50Z"],["dc.date.issued","2001"],["dc.description.abstract","Hydrogen concentration-pressure isotherms of surfactant-stabilized palladium clusters and polymer-embedded palladium clusters with diameters of 2, 3, and 5 nm are measured with the gas sorption method at room temperature. The results show that, compared to bulk palladium, the hydrogen solubility in the a phase of the clusters is enhanced fivefold to tenfold, and the miscibility gap is narrowed. Both results can be explained by assuming that hydrogen occupies the subsurface sites of the palladium clusters. The Pd-H isotherms of all clusters show the existence of hysteresis, even though the formation of misfit dislocations is unfavorable in small clusters. Compared to surfactant-stabilized clusters, the polymer-embedded clusters show slow absorption and desorption kinetics. The absorption kinetics can be described by a diffusion model for the composite polymer-cluster system."],["dc.identifier.doi","10.1103/PhysRevB.64.075408"],["dc.identifier.isi","000170500900088"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20541"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Solubility of hydrogen in single-sized palladium clusters"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","60"],["dc.bibliographiccitation.lastpage","62"],["dc.bibliographiccitation.seriesnr","445/446"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Kuzel, R."],["dc.contributor.author","Becvar, F."],["dc.contributor.author","Cieslar, M."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.editor","Hyodo, Toshio"],["dc.date.accessioned","2018-11-07T10:53:09Z"],["dc.date.available","2018-11-07T10:53:09Z"],["dc.date.issued","2004"],["dc.description.abstract","Changes of the defect structure of niobium induced by hydrogen loading are presented in this work. It was found that annealing of virgin bulk Nb (99.9%) at 1000degreesC for 1h leads to a complete recovery of defects. Subsequently, the defect-free samples were step-by-step electrochemically loaded with hydrogen up to x(H) - 0.06 [H/Nb atom ratio], i.e. in the alpha-phase region, where the Nb-H system represents a single-phase solid solution. The evolution of the microstructure with increasing hydrogen concentration was studied by X-ray diffraction and two complementary techniques of positron annihilation spectroscopy (PAS), namely positron lifetime spectroscopy and slow positron implantation spectroscopy with measurement of Doppler broadening. It was found that new defects were created due to hydrogen loading. The concentration of these hydrogen-induced defects increases with increasing hydrogen concentration. A comparison of PAS results with theoretical calculations revealed that complexes consisting of a vacancy, surrounded likely by four hydrogen atoms, were introduced into the samples due to hydrogen loading."],["dc.identifier.isi","000189406800014"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49288"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","Najko"],["dc.publisher","Trans Tech Publications Ltd"],["dc.publisher.place","Uetikon-Zürich"],["dc.relation.conference","13th International Conference on Positron Annihilation (ICPA-13)"],["dc.relation.crisseries","Materials Science Forum"],["dc.relation.eventend","2003-09-12"],["dc.relation.eventlocation","Kyoto, JAPAN"],["dc.relation.eventstart","2003-09-07"],["dc.relation.isbn","0-87849-936-9"],["dc.relation.ispartof","Positron annihilation"],["dc.relation.ispartofseries","Materials Science Forum; 445/446"],["dc.relation.issn","0255-5476"],["dc.title","Hydrogen-induced defects in niobium studied by positron annihilation"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","484"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","488"],["dc.bibliographiccitation.volume","446"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Danis, Stanislav"],["dc.contributor.author","Melikhova, Oksana"],["dc.contributor.author","Vlach, Martin"],["dc.contributor.author","Zaludova, N."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Muecklich, Arndt"],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Nikitin, E."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T10:57:35Z"],["dc.date.available","2018-11-07T10:57:35Z"],["dc.date.issued","2007"],["dc.description.abstract","H interaction with defects in thin Nb films was investigated in this work. Thin Nb films were prepared by the cold cathode beam sputtering. First, microstructure of the as deposited films was characterized. The films sputtered at room temperature exhibit nanocrystalline grains, while those sputtered at high temperature (T=850 degrees C) are epitaxial. Subsequently, the films were step-by-step electrochemically charged with H. Development of microstructure and evolution of defect structure with increasing H concentration was investigated by slow positron implantation spectroscopy combined with X-ray diffraction. It was found that H is trapped at open-volume defects in the thin films of both kinds. The nanocrystalline films exhibit significantly extended H solubility in the alpha-phase. Formation of the hydride-phase (Nb-H) at higher H concentrations leads to introduction of new defects. These are most probably dislocation loops that are emitted by growing hydride-phase particles. (C) 2007 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2006.12.131"],["dc.identifier.isi","000250822900103"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50290"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","10th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications"],["dc.relation.eventlocation","Lahaina, HI"],["dc.relation.issn","0925-8388"],["dc.title","Positron annihilation study of hydrogen trapping at open-volume defects: Comparison of nanocrystalline and epitaxial Nb thin films"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]