Pub Date : 1988-09-01DOI: 10.1088/0305-4608/18/9/027
P. Gilberd, T. Duffield, C. Guy
Calorimetric measurements on the hysteresis loop of the spin glass CuMn show that the energy changes take place on those legs of the loop which correspond to reversals of the remanent magnetisation and that it is always heating which occurs, irrespective of the direction of the applied magnetic field. Cycling through successive hysteresis loops causes large initial changes in sample heating and loop area, with both of these quantities tending to a temperature-independent limit. Although the limit cycle is displaced from the origin, the thermal energy changes on both irreversible legs are approximately equal, indicating a change of internal magnetic energy on reversal of the remanence. It is argued that the energy released in the initial magnetisation reversals is attributable to irreversible rearrangements of the relative spin directions and that it is only in the limit cycle that energy changes represent exclusively the intrinsic irreversible processes of magnetisation reversal.
{"title":"Calorimetric studies of magnetic hysteresis in CuMn alloys","authors":"P. Gilberd, T. Duffield, C. Guy","doi":"10.1088/0305-4608/18/9/027","DOIUrl":"https://doi.org/10.1088/0305-4608/18/9/027","url":null,"abstract":"Calorimetric measurements on the hysteresis loop of the spin glass CuMn show that the energy changes take place on those legs of the loop which correspond to reversals of the remanent magnetisation and that it is always heating which occurs, irrespective of the direction of the applied magnetic field. Cycling through successive hysteresis loops causes large initial changes in sample heating and loop area, with both of these quantities tending to a temperature-independent limit. Although the limit cycle is displaced from the origin, the thermal energy changes on both irreversible legs are approximately equal, indicating a change of internal magnetic energy on reversal of the remanence. It is argued that the energy released in the initial magnetisation reversals is attributable to irreversible rearrangements of the relative spin directions and that it is only in the limit cycle that energy changes represent exclusively the intrinsic irreversible processes of magnetisation reversal.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"42 1","pages":"2101-2111"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76246885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1088/0305-4608/18/9/006
S. J. Mali, R. M. Singru, Vijay A. Singh, D. Kanhere
The fully self-consistent implementation of the non-local density functional as suggested by Langreth and Mehl (see Phys. Rev. B, vol.28, p.1809, 1983) has been used in conjunction with the atom-in-jellium model to calculate some electronic properties of metallic Li Be, Mg and Al and solid Si. It is found that the non-local density approximation of Langreth and Mehl, when compared with the local density approximation, shows an improvement in the orbital eigenvalues and total energies.
由Langreth和Mehl提出的非局部密度泛函的完全自洽实现(参见物理学)。Rev. B, vol.28, p.1809, 1983)与原子在凝胶中的模型一起用于计算金属Li Be, Mg, Al和固体Si的一些电子性质。研究发现，Langreth和Mehl的非局域密度近似与局域密度近似相比，在轨道特征值和总能量上都有提高。
{"title":"Calculation of electronic properties of some solids using the non-local density approximation","authors":"S. J. Mali, R. M. Singru, Vijay A. Singh, D. Kanhere","doi":"10.1088/0305-4608/18/9/006","DOIUrl":"https://doi.org/10.1088/0305-4608/18/9/006","url":null,"abstract":"The fully self-consistent implementation of the non-local density functional as suggested by Langreth and Mehl (see Phys. Rev. B, vol.28, p.1809, 1983) has been used in conjunction with the atom-in-jellium model to calculate some electronic properties of metallic Li Be, Mg and Al and solid Si. It is found that the non-local density approximation of Langreth and Mehl, when compared with the local density approximation, shows an improvement in the orbital eigenvalues and total energies.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80777784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1088/0305-4608/18/9/017
P. Lindqvist, O. Rapp
The electrical resistivity of amorphous Cu60Ti40 and Cu65Ti35 has been measured at temperatures between 20 mK and 18 K and in magnetic fields up to 4 T. The results are discussed in a framework given by the weak localisation theory including spin-orbit scattering and spin splitting (Fukuyama and Hoshino in 1981 (FH)) and electron-electron interaction theories (Al'tshulet et al. in 1984 (AA), Lee and Ramakrishnan in 1985). Values for the inelastic and spin-orbit scattering lifetimes are derived from the magnetic field dependence of the resistivity, rho (B). Independent determinations from the temperature dependence of rho give qualitative results in agreement with these values. The large spin-orbit scattering time in this alloy system makes a more accurate analysis of rho (T) difficult. The strong dependence on the diffusion constant in the results from rho (B) below 1 K is pointed out. Important differences between the FH and AA formulations of the weak localisation theory are stressed. In particular, the observed temperature dependence of rho (B) in the region where it is linear in square root B can be explained only within the FH theory.
{"title":"Weak localisation and interaction effects in amorphous CuTi alloys","authors":"P. Lindqvist, O. Rapp","doi":"10.1088/0305-4608/18/9/017","DOIUrl":"https://doi.org/10.1088/0305-4608/18/9/017","url":null,"abstract":"The electrical resistivity of amorphous Cu60Ti40 and Cu65Ti35 has been measured at temperatures between 20 mK and 18 K and in magnetic fields up to 4 T. The results are discussed in a framework given by the weak localisation theory including spin-orbit scattering and spin splitting (Fukuyama and Hoshino in 1981 (FH)) and electron-electron interaction theories (Al'tshulet et al. in 1984 (AA), Lee and Ramakrishnan in 1985). Values for the inelastic and spin-orbit scattering lifetimes are derived from the magnetic field dependence of the resistivity, rho (B). Independent determinations from the temperature dependence of rho give qualitative results in agreement with these values. The large spin-orbit scattering time in this alloy system makes a more accurate analysis of rho (T) difficult. The strong dependence on the diffusion constant in the results from rho (B) below 1 K is pointed out. Important differences between the FH and AA formulations of the weak localisation theory are stressed. In particular, the observed temperature dependence of rho (B) in the region where it is linear in square root B can be explained only within the FH theory.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"61 1","pages":"1979-1994"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91087855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1088/0305-4608/18/9/013
A. Hackmann, O. Kanert, H. Kolem, B. Michel, B. Gunther
The atomic diffusion of Cu in solid Au:xCu alloys (x=5.7, 8.2, 9.1, 10.4, 13.2, 17.3 at.%) has been studied by means of solute (63Cu) nuclear spin relaxation (NSR) experiments in the rotating frame (T1p) between ambient temperature and 1100 K. Surprisingly, two distinct diffusion-induced maxima in the relaxation rate could be observed. The high-temperature mechanism around 950 K corresponds to the translational diffusion of Cu in the solid solution phase, as is suggested by comparison with tracer diffusion data. The second relaxation mechanism occurs at fairly low temperatures ( approximately=700 K) with a maximum intensity around 8 at.% Cu. The origin of this contribution to the diffusional NSR rate is not quite clear. The authors attribute it to a short-range ordering effect of Cu atoms in the Au matrix. The activation enthalpies of both types of atomic motion depend only slightly on the Cu concentration.
{"title":"Atomic motion of copper in solid Au:xCu alloys studied by nuclear magnetic resonance","authors":"A. Hackmann, O. Kanert, H. Kolem, B. Michel, B. Gunther","doi":"10.1088/0305-4608/18/9/013","DOIUrl":"https://doi.org/10.1088/0305-4608/18/9/013","url":null,"abstract":"The atomic diffusion of Cu in solid Au:xCu alloys (x=5.7, 8.2, 9.1, 10.4, 13.2, 17.3 at.%) has been studied by means of solute (63Cu) nuclear spin relaxation (NSR) experiments in the rotating frame (T1p) between ambient temperature and 1100 K. Surprisingly, two distinct diffusion-induced maxima in the relaxation rate could be observed. The high-temperature mechanism around 950 K corresponds to the translational diffusion of Cu in the solid solution phase, as is suggested by comparison with tracer diffusion data. The second relaxation mechanism occurs at fairly low temperatures ( approximately=700 K) with a maximum intensity around 8 at.% Cu. The origin of this contribution to the diffusional NSR rate is not quite clear. The authors attribute it to a short-range ordering effect of Cu atoms in the Au matrix. The activation enthalpies of both types of atomic motion depend only slightly on the Cu concentration.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"11 1","pages":"1927-1932"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82375848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/015
O. Lyon, J. Simon
The solute partitioning and the unmixing kinetics of a Cu0.43Ni0.42Fe0.15 alloy have been studied by anomalous small-angle X-ray scattering (ASAXS). From ASAXS data, partial structure factors (PSF) have been extracted: the homoatomic PSF curves cannot account for a pseudobinary system and one has to consider a Ni (or Fe) segregation at the interfaces between the Cu-rich phase and the Ni-Fe phase. The main contribution to the PSF comes nevertheless from the two-phase term which behaves as in the late stage of deep quenches of concentrated binary systems: PSF present a hump which increases and shifts toward low q values as power laws of the aging time: qmvaries as t-0.25, Smvaries as t0.7.
{"title":"An analysis of the partial structure functions in unmixed Cu-Ni-Fe alloys studied by anomalous small-angle X-ray scattering","authors":"O. Lyon, J. Simon","doi":"10.1088/0305-4608/18/8/015","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/015","url":null,"abstract":"The solute partitioning and the unmixing kinetics of a Cu0.43Ni0.42Fe0.15 alloy have been studied by anomalous small-angle X-ray scattering (ASAXS). From ASAXS data, partial structure factors (PSF) have been extracted: the homoatomic PSF curves cannot account for a pseudobinary system and one has to consider a Ni (or Fe) segregation at the interfaces between the Cu-rich phase and the Ni-Fe phase. The main contribution to the PSF comes nevertheless from the two-phase term which behaves as in the late stage of deep quenches of concentrated binary systems: PSF present a hump which increases and shifts toward low q values as power laws of the aging time: qmvaries as t-0.25, Smvaries as t0.7.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"87 4 1","pages":"1787-1799"},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72714224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/014
W. Paszkowicz
Attempts to explain the stoichiometrics of intermetallic compounds in binary phase diagrams are described. The model presented yields compound compositions which are simple rational numbers and is expected to be useful for work on intermetallic phase diagrams. The occurrence of compounds in 10 binary systems (Si-Hf, Co-Y, Hg-Sr, Rh-Gd, Au-Sm, Hg-Ca, Pt-In, Au-In, Fe-Al, and Pd-Ti) is compared with the results of the calculations. It is concluded that a considerable number of compounds occurring in these systems is justified by the proposed hard-spheres packing condition. The dependence of the efficiency of the method on the radius ratio and on the compound components is indicated.
{"title":"Contribution of a hard-spheres packing model to the determination of binary alloy phase diagrams","authors":"W. Paszkowicz","doi":"10.1088/0305-4608/18/8/014","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/014","url":null,"abstract":"Attempts to explain the stoichiometrics of intermetallic compounds in binary phase diagrams are described. The model presented yields compound compositions which are simple rational numbers and is expected to be useful for work on intermetallic phase diagrams. The occurrence of compounds in 10 binary systems (Si-Hf, Co-Y, Hg-Sr, Rh-Gd, Au-Sm, Hg-Ca, Pt-In, Au-In, Fe-Al, and Pd-Ti) is compared with the results of the calculations. It is concluded that a considerable number of compounds occurring in these systems is justified by the proposed hard-spheres packing condition. The dependence of the efficiency of the method on the radius ratio and on the compound components is indicated.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"33 1","pages":"1761-1785"},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81565174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/004
E. Sampathkumaran, N. Ikeda, K. Kohn, R. Vijayaraghavan
The effect of the partial replacement of Bi by Eu, Gd, K and Pb, and Cu by Ni, on the superconducting transition temperature (Tc) of Bi4Ca3Sr3Cu4Oy (y=undetermined) is investigated by DC resistivity (R) and AC susceptibility ( chi ) measurements. Tc is not significantly altered by Eu and Gd substituents (Tc close to 65 K); however, K and Pb substituents tend to enhance the fraction of a phase superconducting around 110 K. Interestingly, for nickel specimens, Tc of a large fraction, as suggested by AC chi data, initially decreases to 40 K with increasing concentration of nickel, followed by an increase, whereas R data shows no appreciable variation of Tc.
{"title":"Influence of chemical substituents on the superconductivity of the system Bi4Ca3Sr3Cu4Oy","authors":"E. Sampathkumaran, N. Ikeda, K. Kohn, R. Vijayaraghavan","doi":"10.1088/0305-4608/18/8/004","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/004","url":null,"abstract":"The effect of the partial replacement of Bi by Eu, Gd, K and Pb, and Cu by Ni, on the superconducting transition temperature (Tc) of Bi4Ca3Sr3Cu4Oy (y=undetermined) is investigated by DC resistivity (R) and AC susceptibility ( chi ) measurements. Tc is not significantly altered by Eu and Gd substituents (Tc close to 65 K); however, K and Pb substituents tend to enhance the fraction of a phase superconducting around 110 K. Interestingly, for nickel specimens, Tc of a large fraction, as suggested by AC chi data, initially decreases to 40 K with increasing concentration of nickel, followed by an increase, whereas R data shows no appreciable variation of Tc.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"358 1","pages":"004"},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76517438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/010
K. O. Jensen, M. Eldrup, N. Pedersen, J. Evans
Bulk copper and nickel samples containing 3 and 5 at. % krypton respectively have been studied by conventional positron annihilation techniques. Most of the emphasis has been placed on the changes in positron lifetime and angular correlation parameters during isochronal annealing from ambient up to near the metal melting points. The study was complemented by transmission and scanning electron microscopy, together with macroscopic measurements of weight and dimensions. These techniques, combined with previous studies, provide a fairly detailed picture of both the as-prepared materials, where the krypton is present as a high density of solid phase precipitates (solid bubbles), and the subsequent marked response of the substructure to annealing. A number of features are of particular interest. The onset temperature for bubble coalescence events is correlated with the melting temperature of the solid Kr inside the bubbles. At higher temperatures extensive swelling is observed prior to and simultaneously with the release of the majority of the krypton. The structure after the Kr release contains micrometre-sized pores and approximately 10 nm bubbles. This structure partly recovers at higher temperatures, but sufficient krypton is retained in the pores to maintain a large swelling up to close to the metal melting points. Positrons are found to become trapped at the Kr-metal interface in Kr bubbles, and there is clear evidence for a quantitative relation between lifetime and Kr density. Both these features are in agreement with the recent theory of Jensen and Nieminen (1987). Finally, positron trapping into dislocations is observed to occur at a rate much lower than that predicted from published specific trapping rates.
{"title":"Annealing behaviour of copper and nickel containing high concentrations of krypton studied by positron annihilation and other techniques","authors":"K. O. Jensen, M. Eldrup, N. Pedersen, J. Evans","doi":"10.1088/0305-4608/18/8/010","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/010","url":null,"abstract":"Bulk copper and nickel samples containing 3 and 5 at. % krypton respectively have been studied by conventional positron annihilation techniques. Most of the emphasis has been placed on the changes in positron lifetime and angular correlation parameters during isochronal annealing from ambient up to near the metal melting points. The study was complemented by transmission and scanning electron microscopy, together with macroscopic measurements of weight and dimensions. These techniques, combined with previous studies, provide a fairly detailed picture of both the as-prepared materials, where the krypton is present as a high density of solid phase precipitates (solid bubbles), and the subsequent marked response of the substructure to annealing. A number of features are of particular interest. The onset temperature for bubble coalescence events is correlated with the melting temperature of the solid Kr inside the bubbles. At higher temperatures extensive swelling is observed prior to and simultaneously with the release of the majority of the krypton. The structure after the Kr release contains micrometre-sized pores and approximately 10 nm bubbles. This structure partly recovers at higher temperatures, but sufficient krypton is retained in the pores to maintain a large swelling up to close to the metal melting points. Positrons are found to become trapped at the Kr-metal interface in Kr bubbles, and there is clear evidence for a quantitative relation between lifetime and Kr density. Both these features are in agreement with the recent theory of Jensen and Nieminen (1987). Finally, positron trapping into dislocations is observed to occur at a rate much lower than that predicted from published specific trapping rates.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"25 1","pages":"1703-1724"},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86910841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/009
M. J. Sabochick, S. Yip
The migration energies of tri- and tetravacancies in copper are calculated to be 0.56 eV and 0.38 eV, respectively, using a new energy minimisation scheme and a first-principles interatomic potential. Comparison with the previously calculated single and divacancy migration energies of 0.82 and 0.55 eV, respectively, indicates that the tri- and tetravacancies are very mobile in copper. The calculated binding and migration energies were used in a rate equation model which predicts the concentrations of vacancy defects during quenching and electron-irradiation experiments. The predicted activation energy of the model follows the same general behaviour as that measured in annealing experiments. The maximum concentrations of tri- and tetravacancies predicted by the model are very low (less than 0.001 p.p.m.), which suggests that these defects many not be observable using experimental techniques.
{"title":"Migration energy calculations for small vacancy clusters in copper","authors":"M. J. Sabochick, S. Yip","doi":"10.1088/0305-4608/18/8/009","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/009","url":null,"abstract":"The migration energies of tri- and tetravacancies in copper are calculated to be 0.56 eV and 0.38 eV, respectively, using a new energy minimisation scheme and a first-principles interatomic potential. Comparison with the previously calculated single and divacancy migration energies of 0.82 and 0.55 eV, respectively, indicates that the tri- and tetravacancies are very mobile in copper. The calculated binding and migration energies were used in a rate equation model which predicts the concentrations of vacancy defects during quenching and electron-irradiation experiments. The predicted activation energy of the model follows the same general behaviour as that measured in annealing experiments. The maximum concentrations of tri- and tetravacancies predicted by the model are very low (less than 0.001 p.p.m.), which suggests that these defects many not be observable using experimental techniques.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"64 1","pages":"1689-1701"},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87147097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-08-01DOI: 10.1088/0305-4608/18/8/001
S. Giorgio, J. Urban
Small silver clusters have been investigated by electron microscopy. A bimodal size distribution is formed containing particles of diameter 1-2 nm and 4-8 nm. Among the largest particles icosahedra and cuboctahedra appear with equal frequency in HREM. 1 nm size icosahedra, however, could not be found, while cuboctahedra of this size could be resolved. Computer simulations of high resolution images for both structures reveal that icosahedra are more difficult to resolve under the experimental conditions. A dilation of approximately 5% of the lattice parameter could be measured for 1 nm particles. For 2 nm particles, this dilation drops to 2.5% compared with the bulk value of the particles larger than 3 nm.
{"title":"Structure of 1 nm silver clusters","authors":"S. Giorgio, J. Urban","doi":"10.1088/0305-4608/18/8/001","DOIUrl":"https://doi.org/10.1088/0305-4608/18/8/001","url":null,"abstract":"Small silver clusters have been investigated by electron microscopy. A bimodal size distribution is formed containing particles of diameter 1-2 nm and 4-8 nm. Among the largest particles icosahedra and cuboctahedra appear with equal frequency in HREM. 1 nm size icosahedra, however, could not be found, while cuboctahedra of this size could be resolved. Computer simulations of high resolution images for both structures reveal that icosahedra are more difficult to resolve under the experimental conditions. A dilation of approximately 5% of the lattice parameter could be measured for 1 nm particles. For 2 nm particles, this dilation drops to 2.5% compared with the bulk value of the particles larger than 3 nm.","PeriodicalId":16828,"journal":{"name":"Journal of Physics F: Metal Physics","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1988-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78140441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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