Güthoff, Friedrich

[["dc.bibliographiccitation.firstpage","240"],["dc.bibliographiccitation.journal","Physica B Condensed Matter"],["dc.bibliographiccitation.lastpage","241"],["dc.bibliographiccitation.volume","276"],["dc.contributor.author","Gibhardt, Holger"],["dc.contributor.author","Eckold, Goetz"],["dc.contributor.author","Guthoff, F."],["dc.date.accessioned","2018-11-07T09:39:40Z"],["dc.date.available","2018-11-07T09:39:40Z"],["dc.date.issued","2000"],["dc.description.abstract","Real-time stroboscopic neutron scattering has been used to investigate the time evolution of the phase transition in quartz Under periodic external stresses relaxation times of the order 1 s are observed and the incommensurate phase exhibits a different stability regime as compared to static conditions. (C) 2000 Elsevier Science B.V. All rights reserved."],["dc.identifier.doi","10.1016/S0921-4526(99)01424-6"],["dc.identifier.isi","000086413000100"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33335"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","2nd European Conference on Neutron Scattering (ECNS 99)"],["dc.relation.eventlocation","BUDAPEST, HUNGARY"],["dc.relation.issn","1873-2135"],["dc.relation.issn","0921-4526"],["dc.title","Kinetics of the stress induced phase transition in quartz by real-time neutron scattering"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","11521"],["dc.bibliographiccitation.issue","50"],["dc.bibliographiccitation.journal","Journal of Physics Condensed Matter"],["dc.bibliographiccitation.lastpage","11530"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Caspary, D."],["dc.contributor.author","Eckold, Goetz"],["dc.contributor.author","Guthoff, F."],["dc.contributor.author","Pyckhout-Hintzen, W."],["dc.date.accessioned","2018-11-07T11:19:07Z"],["dc.date.available","2018-11-07T11:19:07Z"],["dc.date.issued","2001"],["dc.description.abstract","The kinetic of decomposition in the quasi-binary ionic system AgCl-NaCl has been studied by means of time-resolved neutron diffraction and small-angle neutron scattering. The coherent critical point is estimated as 447 +/- 3 K, 24 K below the upper critical binodal temperature. The chemical decomposition is almost completed in the first 200 s irrespective of the temperature. The mechanical relaxation of the lattice, however, takes place on a much longer timescale and is dominated by coherency strains leading to metastable intermediate states."],["dc.identifier.doi","10.1088/0953-8984/13/50/311"],["dc.identifier.isi","000173436600015"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55194"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","1361-648X"],["dc.relation.issn","0953-8984"],["dc.title","Kinetics of decomposition in ionic solids: II. Neutron scattering study of the system AgCl-NaCl"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","105013"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Materials Research Express"],["dc.bibliographiccitation.volume","2"],["dc.contributor.affiliation","Güthoff, F;"],["dc.contributor.affiliation","Zhang, B;"],["dc.contributor.affiliation","Eckold, G;"],["dc.contributor.author","Guethoff, Friedrich"],["dc.contributor.author","Zhang, B."],["dc.contributor.author","Eckold, Goetz"],["dc.date.accessioned","2018-11-07T09:50:24Z"],["dc.date.available","2018-11-07T09:50:24Z"],["dc.date.issued","2015"],["dc.date.updated","2022-02-09T13:18:42Z"],["dc.description.abstract","In quasi binary systems like AgBr-NaBr the demixing from the homogeneous high temperature phase into separated phases is a complex process that depends on the ageing temperature as well as on the quench rate. Spinodal decomposition and nucleation processes can be distinguished which lead, however, to the same final equilibrium state. Using frequency modulated scanning force microscopy we aimed to distinguish the demixed phases and their morphologies on a nm-scale at room temperature for samples with different concentration. While no contrast between the different phases are observed in the usual topographic mode, a modified evaluation of Kelvin experiments allows the distinction of silver-and sodium enriched phases. Moreover, direct evidence is found for concentration fluctuations which are characteristic for spinodal decomposition."],["dc.identifier.doi","10.1088/2053-1591/2/10/105013"],["dc.identifier.eissn","2053-1591"],["dc.identifier.isi","000370058600013"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/13118"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35704"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","IOP Publishing"],["dc.relation.issn","2053-1591"],["dc.rights.access","openAccess"],["dc.rights.uri","http://creativecommons.org/licenses/by/3.0/"],["dc.title","Imaging chemical concentration pattern and early stages of spinodal decomposition in the AgxNa1-xBr system by scanning force microscopy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","PII S0953-8984(03)63779-3"],["dc.bibliographiccitation.firstpage","6415"],["dc.bibliographiccitation.issue","37"],["dc.bibliographiccitation.journal","Journal of Physics Condensed Matter"],["dc.bibliographiccitation.lastpage","6426"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Caspary, D."],["dc.contributor.author","Eckold, Goetz"],["dc.contributor.author","Elter, P."],["dc.contributor.author","Gibhardt, Holger"],["dc.contributor.author","Guthoff, F."],["dc.contributor.author","Demmel, F."],["dc.contributor.author","Hoser, A."],["dc.contributor.author","Schmidt, W."],["dc.contributor.author","Schweika, W."],["dc.date.accessioned","2018-11-07T10:36:04Z"],["dc.date.available","2018-11-07T10:36:04Z"],["dc.date.issued","2003"],["dc.description.abstract","The dynamics of mixed single crystals of AgxNa1-xCl has been investigated by inelastic neutron scattering before and after chemical demixing. In the homogeneous phase, the concentration dependence of acoustic phonons reveals that doping of NaCl with silver chloride leads to a considerable softening of the lattice, while the elastic properties of AgCl are almost independent of sodium chloride additives. After quenching into the miscibility gap, the phase separation is associated with a well-defined splitting of acoustic phonons which provide the most direct information about the underlying mechanism. In contrast to the local dynamical properties, the lattice structure is essentially determined by coherency strains which hinder the relaxation of lattice parameters. Thus diffraction and inelastic scattering yield independent and complementary information about demixing processes in ionic solids."],["dc.identifier.doi","10.1088/0953-8984/15/37/009"],["dc.identifier.isi","000185909800017"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45239"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","0953-8984"],["dc.title","The influence of demixing on the dynamics of ionic solids: inelastic neutron scattering from Ag(x)Na(1-x)C1 single crystals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","S1169"],["dc.bibliographiccitation.journal","Applied Physics A"],["dc.bibliographiccitation.lastpage","S1171"],["dc.bibliographiccitation.volume","74"],["dc.contributor.author","Elter, P."],["dc.contributor.author","Eckold, Goetz"],["dc.contributor.author","Caspary, D."],["dc.contributor.author","Guthoff, F."],["dc.contributor.author","Hoser, A."],["dc.date.accessioned","2018-11-07T09:43:07Z"],["dc.date.available","2018-11-07T09:43:07Z"],["dc.date.issued","2002"],["dc.description.abstract","Real-time inelastic neutron scattering has been used to characterise the mechanism of decomposition in AgxNa1-xBr mixed single crystals well below the critical temperature on a microscopic scale. The chemical demixing process is associated with a splitting of acoustic phonon branches, which is observed to take place within some 100 s. Interestingly, the Bragg reflections exhibit a completely different time behaviour: the adaptation of the equilibrium lattice parameters occurs on a much longer time scale. Hence, decomposition is governed by large coherency strains which persist over a long period of time. Only in a second stage does the crystal lattice relax into the final equilibrium state."],["dc.identifier.doi","10.1007/s003390201553"],["dc.identifier.isi","000181219600079"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34104"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","New york"],["dc.relation.conference","International Conference on Neutron Scattering"],["dc.relation.eventlocation","MUNICH, GERMANY"],["dc.relation.issn","0947-8396"],["dc.title","Time-evolution of phonon spectra during decomposition in AgxNa1-xBr ionic crystals"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","83"],["dc.bibliographiccitation.issue","1-3"],["dc.bibliographiccitation.journal","Physica B Condensed Matter"],["dc.bibliographiccitation.lastpage","86"],["dc.bibliographiccitation.volume","350"],["dc.contributor.author","Eckold, Goetz"],["dc.contributor.author","Caspary, D."],["dc.contributor.author","Elter, P."],["dc.contributor.author","Guthoff, F."],["dc.contributor.author","Hoser, A."],["dc.contributor.author","Schmidt, W."],["dc.date.accessioned","2018-11-07T10:47:19Z"],["dc.date.available","2018-11-07T10:47:19Z"],["dc.date.issued","2004"],["dc.description.abstract","Time-resolved inelastic neutron scattering from acoustic phonons has been used to characterise the mechanism of demixing in ionic crystals of the silver alkali halide type. Stroboscopic techniques allow to study the time-evolution of phonon spectra during the phase separation in AgBr-NaBr and AgCl-NaCl single crystals on a time scale of seconds. These data provide the most direct information about changes of interatomic interactions. Characteristic differences are observed for ageing temperatures above and below the spinodal temperature which allow to distinguish between different mechanisms based on nucleation on the one hand and concentration fluctuations on the other. (C) 2004 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.physb.2004.04.058"],["dc.identifier.isi","000223285700021"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/47937"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","3rd European Conference on Neutron Scattering (ECNS 2003)"],["dc.relation.eventlocation","Montpellier, FRANCE"],["dc.relation.issn","0921-4526"],["dc.title","Time-resolved phonons as a microscopic probe for demixing processes"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","255401"],["dc.bibliographiccitation.issue","25"],["dc.bibliographiccitation.journal","Journal of Physics Condensed Matter"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Davaasambuu, Jav"],["dc.contributor.author","Guethoff, Friedrich"],["dc.contributor.author","Petri, M."],["dc.contributor.author","Hradil, Klaudia"],["dc.contributor.author","Schober, H."],["dc.contributor.author","Ollivier, J."],["dc.contributor.author","Eckold, Goetz"],["dc.date.accessioned","2018-11-07T09:09:10Z"],["dc.date.available","2018-11-07T09:09:10Z"],["dc.date.issued","2012"],["dc.description.abstract","The dynamics of silver-alkali halide mixed single crystals (AgxNa1-xBr, x = 0.23, 0.35, 0.40 and 0.70) were studied by inelastic neutron scattering during the process of spinodal decomposition. Using the thermal three-axes spectrometer PUMA as well as the time-of-flight spectrometer IN5, the time evolution of phonons was observed in time-resolved, stroboscopic measurements. Complementary to the study of long wavelength acoustic phonons, as studied previously, we extended these investigations to Brillouin-zone boundary modes that are particularly sensitive to variations of the local structure. Starting from the homogeneous mixed phase the behaviour of these modes during demixing is observed in real-time. A simple dynamical model based on local structure variants helps to interpret the results. It is shown that the phonon lifetimes vary strongly during the phase separation and increase drastically during the coarsening process. Up to a critical size of precipitates of about 10 nm, zone-boundary modes are found to be strongly damped, while beyond the line widths are reduced to the experimental resolution. This finding leads to the conclusion that the typical mean free path of these modes is of the order of 10 nm, which corresponds to 20 unit cells."],["dc.description.sponsorship","DFG [EC 153/3-1]"],["dc.identifier.doi","10.1088/0953-8984/24/25/255401"],["dc.identifier.isi","000304875600010"],["dc.identifier.pmid","22634583"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26195"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","0953-8984"],["dc.title","Phonon-lifetimes in demixing systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","413"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS"],["dc.bibliographiccitation.lastpage","419"],["dc.bibliographiccitation.volume","225"],["dc.contributor.author","Davaasambuu, Jav"],["dc.contributor.author","Guethoff, Friedrich"],["dc.contributor.author","Hoelzel, Markus"],["dc.contributor.author","Senyshyn, Anatoliy"],["dc.contributor.author","Radulescu, Aurel"],["dc.contributor.author","Eckold, Goetz"],["dc.date.accessioned","2018-11-07T09:02:06Z"],["dc.date.available","2018-11-07T09:02:06Z"],["dc.date.issued","2011"],["dc.description.abstract","Thermal properties of CoCl2, MnCl2 and their mixed crystals are investigated by means of temperature dependent neutron powder diffraction and time-resolved small angle neutron scattering. The coefficients of thermal expansion of these crystals have been determined as a function of temperature. The temperature-induced structural variations can be explained by distortions of CoCl5/MnCl6 octahedra and changes in Co/Mn-Cl bond lengths. CoCl2 and MnCl2 form homogeneous solid solutions in the entire temperature range between the solidus and 50 K. There is no indication of any miscibility gap as predicted from thermodynamic calculations."],["dc.description.sponsorship","DFG [EC 153/3-1]"],["dc.identifier.doi","10.1524/zpch.2011.0115"],["dc.identifier.isi","000290690700003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24599"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oldenbourg Verlag"],["dc.relation.issn","0942-9352"],["dc.title","Phase Behaviour of CoCl2-MnCl2 Mixed Crystals"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","10"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Ferroelectrics"],["dc.bibliographiccitation.lastpage","17"],["dc.bibliographiccitation.volume","540"],["dc.contributor.author","Kofahl, Claudia"],["dc.contributor.author","Güthoff, Friedrich"],["dc.contributor.author","Eckold, Götz"],["dc.date.accessioned","2020-04-03T13:40:31Z"],["dc.date.available","2020-04-03T13:40:31Z"],["dc.date.issued","2019"],["dc.identifier.doi","10.1080/00150193.2019.1611115"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/63636"],["dc.relation.issn","0015-0193"],["dc.relation.issn","1563-5112"],["dc.title","Direct observation of polar nanodomains in the incommensurate phase of (K0.96Rb0.04)2ZnCl4 crystals using piezo force microscopy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]