Pub Date : 2008-12-01DOI: 10.1142/S1793617908000203
D. Sprouster, R. Giulian, P. Kluth, L. Araujo, G. Foran, D. Cookson, M. Ridgway
Ion implantation of Co into silica layers and subsequent thermal annealing were used to form Co nanoparticles. Structural characterization was performed using X-ray Absorption Spectroscopy and Small Angle X-ray Scattering to determine, respectively, the local atomic structure and size distribution of the Co nanoparticles as a function of annealing temperature. For decreasing nanoparticle size, a bond-length contraction, an increase in Debye–Waller factor and a reduction in coordination number were observed. The bond-length contraction was related to the capillary pressure in the nanoparticles while an increase in Debye–Waller factor reflected an increase in disorder attributed to the high surface-area-to-volume ratio of small nanoparticles. X-ray Absorption Near Edge Structure spectroscopy revealed that the annealing conditions had a significant effect on the nanoparticle crystal structure and oxidised Co fraction.
{"title":"SYNCHROTRON RADIATION CHARACTERIZATION OF COBALT NANOPARTICLES FORMED BY ION IMPLANTATION","authors":"D. Sprouster, R. Giulian, P. Kluth, L. Araujo, G. Foran, D. Cookson, M. Ridgway","doi":"10.1142/S1793617908000203","DOIUrl":"https://doi.org/10.1142/S1793617908000203","url":null,"abstract":"Ion implantation of Co into silica layers and subsequent thermal annealing were used to form Co nanoparticles. Structural characterization was performed using X-ray Absorption Spectroscopy and Small Angle X-ray Scattering to determine, respectively, the local atomic structure and size distribution of the Co nanoparticles as a function of annealing temperature. For decreasing nanoparticle size, a bond-length contraction, an increase in Debye–Waller factor and a reduction in coordination number were observed. The bond-length contraction was related to the capillary pressure in the nanoparticles while an increase in Debye–Waller factor reflected an increase in disorder attributed to the high surface-area-to-volume ratio of small nanoparticles. X-ray Absorption Near Edge Structure spectroscopy revealed that the annealing conditions had a significant effect on the nanoparticle crystal structure and oxidised Co fraction.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122137703","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 : 2008-12-01DOI: 10.1142/S1793617908000239
R. Giulian, P. Kluth, D. Sprouster, L. Araujo, D. Llewellyn, A. Byrne, D. Cookson, M. Ridgway
Elongated Pt nanocrystals (NCs) formed in SiO2 by ion implantation, thermal annealing and swift heavy ion irradiation (SHII) were analyzed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements. Transmission SAXS measurements were performed in samples aligned at different angles relative to the photon beam resulting in nonisotropic scattering and thus enabling the three-dimensional analysis of the NCs. Selected angular sectors of the detector were integrated and analyzed separately, leading to the individual evaluation of both the major and minor dimensions of the rod-shaped NCs. This method enables the use of well-established spherical models for the SAXS data analysis and yielded good agreement with TEM results. Corrections to the amplitude of the SAXS diameter distributions to overcome the disparities between the spherical models and the nonspherical particles are also presented.
{"title":"ANGLE-DEPENDENT MEASUREMENTS OF ELONGATED PLATINUM NANOCRYSTALS USING SMALL ANGLE X-RAY SCATTERING","authors":"R. Giulian, P. Kluth, D. Sprouster, L. Araujo, D. Llewellyn, A. Byrne, D. Cookson, M. Ridgway","doi":"10.1142/S1793617908000239","DOIUrl":"https://doi.org/10.1142/S1793617908000239","url":null,"abstract":"Elongated Pt nanocrystals (NCs) formed in SiO2 by ion implantation, thermal annealing and swift heavy ion irradiation (SHII) were analyzed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements. Transmission SAXS measurements were performed in samples aligned at different angles relative to the photon beam resulting in nonisotropic scattering and thus enabling the three-dimensional analysis of the NCs. Selected angular sectors of the detector were integrated and analyzed separately, leading to the individual evaluation of both the major and minor dimensions of the rod-shaped NCs. This method enables the use of well-established spherical models for the SAXS data analysis and yielded good agreement with TEM results. Corrections to the amplitude of the SAXS diameter distributions to overcome the disparities between the spherical models and the nonspherical particles are also presented.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127525492","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 : 2008-12-01DOI: 10.1142/S1793617908000215
P. Vahdani, A. S. Rozatian, J. Amighian
In this paper, magnetic and structural properties as well as the interface morphology of a series of sputtered Co/Pd multilayer thin films have been investigated. Interface morphology has been studied from grazing incidence specular and off-specular X-ray measurements using synchrotron radiation. High-angle X-ray diffraction measurements indicate a modulated structure which is strongly textured grown along (111) direction. The relation between intensity and the number of bilayers for different peaks of high-angle X-ray diffraction measurements has been investigated and compared to the grazing incidence X-ray scattering results. Vibrating sample magnetometer measurements have shown perpendicular magnetic anisotropy for all samples with Keff reaching highest value for those samples with highest fractal parameter.
{"title":"ANISOTROPY AND STRUCTURAL CHARACTERIZATION OF Co/Pd MULTILAYER THIN FILMS","authors":"P. Vahdani, A. S. Rozatian, J. Amighian","doi":"10.1142/S1793617908000215","DOIUrl":"https://doi.org/10.1142/S1793617908000215","url":null,"abstract":"In this paper, magnetic and structural properties as well as the interface morphology of a series of sputtered Co/Pd multilayer thin films have been investigated. Interface morphology has been studied from grazing incidence specular and off-specular X-ray measurements using synchrotron radiation. High-angle X-ray diffraction measurements indicate a modulated structure which is strongly textured grown along (111) direction. The relation between intensity and the number of bilayers for different peaks of high-angle X-ray diffraction measurements has been investigated and compared to the grazing incidence X-ray scattering results. Vibrating sample magnetometer measurements have shown perpendicular magnetic anisotropy for all samples with Keff reaching highest value for those samples with highest fractal parameter.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125798438","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 : 2008-12-01DOI: 10.1142/S1793617908000276
A. Nikulin, R. Dilanian, B. M. Gable, B. C. Muddle, J. Hester, T. Ishikawa, P. Yang, H. Moser
We report a novel approach to X-ray diffraction data analysis for nondestructive determination of the shape of nanoscale particles and clusters in three dimensions with a spatial resolution of a few nanometers. The advantage of the proposed approach is that it does not require a coherent X-ray source and therefore is suitable for almost any synchrotron radiation beamline and many laboratory sources. The technique is insensitive to the coherence of the X-rays, and 3D reconstruction of a modal image is possible without tomographic synthesis, rendering the approach suitable for laboratory facilities. Successful application of the technique to the characterization of nanoparticulate in a range of dispersed-phase nanocomposite structures illustrates this novel approach.
{"title":"Nondestructive three-dimensional x-ray diffraction imaging of nanoscale particles","authors":"A. Nikulin, R. Dilanian, B. M. Gable, B. C. Muddle, J. Hester, T. Ishikawa, P. Yang, H. Moser","doi":"10.1142/S1793617908000276","DOIUrl":"https://doi.org/10.1142/S1793617908000276","url":null,"abstract":"We report a novel approach to X-ray diffraction data analysis for nondestructive determination of the shape of nanoscale particles and clusters in three dimensions with a spatial resolution of a few nanometers. The advantage of the proposed approach is that it does not require a coherent X-ray source and therefore is suitable for almost any synchrotron radiation beamline and many laboratory sources. The technique is insensitive to the coherence of the X-rays, and 3D reconstruction of a modal image is possible without tomographic synthesis, rendering the approach suitable for laboratory facilities. Successful application of the technique to the characterization of nanoparticulate in a range of dispersed-phase nanocomposite structures illustrates this novel approach.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129630506","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 : 2008-12-01DOI: 10.1142/S1793617908000185
Hsin-Liang Huang, H. -. Wang, H. Wang, Yu-Ling Wei
Speciation of copper and zinc (1:1) in MCM-41 has been studied by X-ray absorption near edge structural (XANES) and X-ray absorption fine structural (EXAFS) spectroscopies in the present work. The least-square fitted XANES spectra show that Cu(II) and Zn(II) are the major copper and zinc species, respectively in the channels of MCM-41 during calcination at 573–1173 K. The EXAFS data indicate that copper in MCM-41 possesses a Cu–O bond distance of 1.97 A with a coordination number (CN) of 3.4. During calcination at 573–1173 K, about 3.8–4.2 nearest oxygen atoms are bonded to the central copper atoms with Cu–O bond distances of 1.95–1.96 A in MCM-41. A small amount of Cu–Zn alloy may be formed during calcination. Existence of Zn–O)–Si (3.05–3.11 A) with CNs of 1.7–2.3 is also observed by EXAFS, suggesting an interaction between zinc and the framework SiO2 of MCM-41 during calcination.
{"title":"INTERACTIONS OF COPPER AND ZINC IN MCM-41","authors":"Hsin-Liang Huang, H. -. Wang, H. Wang, Yu-Ling Wei","doi":"10.1142/S1793617908000185","DOIUrl":"https://doi.org/10.1142/S1793617908000185","url":null,"abstract":"Speciation of copper and zinc (1:1) in MCM-41 has been studied by X-ray absorption near edge structural (XANES) and X-ray absorption fine structural (EXAFS) spectroscopies in the present work. The least-square fitted XANES spectra show that Cu(II) and Zn(II) are the major copper and zinc species, respectively in the channels of MCM-41 during calcination at 573–1173 K. The EXAFS data indicate that copper in MCM-41 possesses a Cu–O bond distance of 1.97 A with a coordination number (CN) of 3.4. During calcination at 573–1173 K, about 3.8–4.2 nearest oxygen atoms are bonded to the central copper atoms with Cu–O bond distances of 1.95–1.96 A in MCM-41. A small amount of Cu–Zn alloy may be formed during calcination. Existence of Zn–O)–Si (3.05–3.11 A) with CNs of 1.7–2.3 is also observed by EXAFS, suggesting an interaction between zinc and the framework SiO2 of MCM-41 during calcination.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"311 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132861907","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 : 2008-12-01DOI: 10.1142/S1793617908000288
Y. H. Yu, M. Lai, L. Lu, G. Zheng
A new experimental method for determining elastic constants of thin films is proposed. The curvatures of the single crystal substrates before and after depositing thin film are first measured using high-resolution X-ray rocking curve technique with high quality monochromatic and high intensity synchrotron radiation. The residual stress in the film is then calculated from the change in substrate curvature based on the well-known modified Stoney's equation. The formulae for calculating thin film's Young's modulus and Poisson's ratio are deduced based on measured residual stress and the lattice spacing dψ versus sin2ψ curves of the film before and after an unknown mechanical loading. LaNiO3 film grown on single crystal silicon substrate using pulsed laser deposition is employed to demonstrate the measurement method.
{"title":"MEASUREMENT OF YOUNG'S MODULUS AND POISSON'S RATIO OF THIN FILMS BY SYNCHROTRON X-RAY DIFFRACTION","authors":"Y. H. Yu, M. Lai, L. Lu, G. Zheng","doi":"10.1142/S1793617908000288","DOIUrl":"https://doi.org/10.1142/S1793617908000288","url":null,"abstract":"A new experimental method for determining elastic constants of thin films is proposed. The curvatures of the single crystal substrates before and after depositing thin film are first measured using high-resolution X-ray rocking curve technique with high quality monochromatic and high intensity synchrotron radiation. The residual stress in the film is then calculated from the change in substrate curvature based on the well-known modified Stoney's equation. The formulae for calculating thin film's Young's modulus and Poisson's ratio are deduced based on measured residual stress and the lattice spacing dψ versus sin2ψ curves of the film before and after an unknown mechanical loading. LaNiO3 film grown on single crystal silicon substrate using pulsed laser deposition is employed to demonstrate the measurement method.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120965345","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 : 2008-12-01DOI: 10.1142/S1793617908000227
L. Araujo, R. Giulian, P. Kluth, B. Johannessen, D. Cookson, G. Foran, M. Ridgway
We report on the atomic level structural properties of Ge nanocrystals (Ge NCs) grown by ion implantation and thermal annealing. The synchrotron-based techniques of extended X-ray absorption fine structure (EXAFS) spectroscopy and small angle X-ray scattering (SAXS) were applied to characterize the Ge NCs. Four different size distributions of Ge NCs were produced in amorphous SiO2 matrices, with mean diameters ranging from 4.0 to 9.0 nm as verified by SAXS measurements. The decrease in size, or increase in surface-to-volume ratio, for the NCs leads to a decrease in the crystalline-like features in the X-ray absorption near-edge structure (XANES) and EXAFS regions of the X-ray absorption spectra. It also yields a decrease in coordination number and an increase in mean interatomic distance, structural disorder, and asymmetry of the interatomic distance distribution. By comparison with bulk standards, the NCs are described as a combination of crystalline Ge core and surrounding amorphous Ge-like surface layer.
{"title":"PROPERTIES OF Ge NANOCRYSTALS DETERMINED BY EXAFS AND SAXS","authors":"L. Araujo, R. Giulian, P. Kluth, B. Johannessen, D. Cookson, G. Foran, M. Ridgway","doi":"10.1142/S1793617908000227","DOIUrl":"https://doi.org/10.1142/S1793617908000227","url":null,"abstract":"We report on the atomic level structural properties of Ge nanocrystals (Ge NCs) grown by ion implantation and thermal annealing. The synchrotron-based techniques of extended X-ray absorption fine structure (EXAFS) spectroscopy and small angle X-ray scattering (SAXS) were applied to characterize the Ge NCs. Four different size distributions of Ge NCs were produced in amorphous SiO2 matrices, with mean diameters ranging from 4.0 to 9.0 nm as verified by SAXS measurements. The decrease in size, or increase in surface-to-volume ratio, for the NCs leads to a decrease in the crystalline-like features in the X-ray absorption near-edge structure (XANES) and EXAFS regions of the X-ray absorption spectra. It also yields a decrease in coordination number and an increase in mean interatomic distance, structural disorder, and asymmetry of the interatomic distance distribution. By comparison with bulk standards, the NCs are described as a combination of crystalline Ge core and surrounding amorphous Ge-like surface layer.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134097393","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 : 2008-12-01DOI: 10.1142/S1793617908000161
T. Hori, A. Miyamoto, K. Goto, H. Tsutsui
Hiroshima Synchrotron Radiation Center (HSRC) is a common facility for research and education in the field of synchrotron radiation science in Japan. The major role of the facility is to promote nationwide SR research activities in materials science, especially in solid state physics, and education in the related fields simultaneously. HiSOR is a compact synchrotron radiation source of HSRC constructed in 1996 as a typical VUV — soft X-ray source (0.87 keV critical photon energy) similar to Helios in Singapore. Because of a compact racetrack-type ring, its natural emittance 400π nm · rad is not so small as the other standard-sized rings. There are two undulators, one linear for 26–300 eV range and the other helical/linear for 4–40 eV. The most outstanding feature of the facility lies in the good combination with beamlines to attain high-resolution (below 1 meV) for photoemission spectroscopy. It is routinely operated from 09:00 to 20:00 on weekdays at the stored current starting from 350 mA with 8 h lifetime at 300 mA. HiSOR has been running over 10 years, thus, it is time to think about the future improvements of the facility. The motivation is to pursue the leading position in the field of materials science (solid state physics) using SR for high-resolution photoemission spectroscopy. Some candidates for the upgraded HiSOR are presented.
{"title":"PRESENT STATUS AND FUTURE PLAN OF COMPACT SR RING HiSOR","authors":"T. Hori, A. Miyamoto, K. Goto, H. Tsutsui","doi":"10.1142/S1793617908000161","DOIUrl":"https://doi.org/10.1142/S1793617908000161","url":null,"abstract":"Hiroshima Synchrotron Radiation Center (HSRC) is a common facility for research and education in the field of synchrotron radiation science in Japan. The major role of the facility is to promote nationwide SR research activities in materials science, especially in solid state physics, and education in the related fields simultaneously. HiSOR is a compact synchrotron radiation source of HSRC constructed in 1996 as a typical VUV — soft X-ray source (0.87 keV critical photon energy) similar to Helios in Singapore. Because of a compact racetrack-type ring, its natural emittance 400π nm · rad is not so small as the other standard-sized rings. There are two undulators, one linear for 26–300 eV range and the other helical/linear for 4–40 eV. The most outstanding feature of the facility lies in the good combination with beamlines to attain high-resolution (below 1 meV) for photoemission spectroscopy. It is routinely operated from 09:00 to 20:00 on weekdays at the stored current starting from 350 mA with 8 h lifetime at 300 mA. HiSOR has been running over 10 years, thus, it is time to think about the future improvements of the facility. The motivation is to pursue the leading position in the field of materials science (solid state physics) using SR for high-resolution photoemission spectroscopy. Some candidates for the upgraded HiSOR are presented.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130392396","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 : 2008-12-01DOI: 10.1142/S1793617908000252
R. Maaß, S. Petegem, H. Swygenhoven, D. Grolimund, P. Derlet, C. Volkert
We present in situ and ex situ Laue micro-diffraction experiments on micron-sized single crystal pillars. We show that the focused ion beam technique introduces measurable damage in Si pillars. The dynamics of the Laue patterns of Au pillars demonstrate the occurrence of crystal rotation and strengthening is explained by plasticity starting on a slip system that is geometrically not predicted but selected because of the character of the pre-existing strain gradient.
{"title":"IN SITU TIME RESOLVED LAUE DIFFRACTION DURING MICRO-COMPRESSION EXPERIMENTS","authors":"R. Maaß, S. Petegem, H. Swygenhoven, D. Grolimund, P. Derlet, C. Volkert","doi":"10.1142/S1793617908000252","DOIUrl":"https://doi.org/10.1142/S1793617908000252","url":null,"abstract":"We present in situ and ex situ Laue micro-diffraction experiments on micron-sized single crystal pillars. We show that the focused ion beam technique introduces measurable damage in Si pillars. The dynamics of the Laue patterns of Au pillars demonstrate the occurrence of crystal rotation and strengthening is explained by plasticity starting on a slip system that is geometrically not predicted but selected because of the character of the pre-existing strain gradient.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133020269","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 : 2008-12-01DOI: 10.1142/S1793617908000148
K. Soda, Hidetoshi Miyazaki, Koji Yamamoto, T. Mochizuki, M. Inukai, Masahiko Kato, S. Yagi, Y. Nishino
The electronic structures of Heusler-type Fe2VAl-based alloys, n-type thermoelectric alloys Fe2VAl1-zXz(X = Si, Ge) and p-type one Fe2(V1-yTiy)Al, have been investigated by photoelectron spectroscopy with use of synchrotron radiation as an excitation photon source. Observed valence-band spectra of Fe2VAl agree quite well with the predicted density of states with a sharp pseudogap across the Fermi energy EF. Small substitution in Fe2VAl1-zXz and Fe2(V1-yTiy)Al reveals a rigid-band-like energy shift of the valence band, although the observed shift is smaller than expected in the rigid band model. Further substitution causes the modification of the electronic structure near EF and the appearance of mid-pseudogap states. However, the dependence of the thermoelectric properties of these alloys on substitution can be qualitatively explained by the observed change in the electronic structure near EF.
{"title":"SYNCHROTRON RADIATION PHOTOELECTRON STUDY OF HEUSLER-TYPE Fe2VAl-BASED ALLOYS","authors":"K. Soda, Hidetoshi Miyazaki, Koji Yamamoto, T. Mochizuki, M. Inukai, Masahiko Kato, S. Yagi, Y. Nishino","doi":"10.1142/S1793617908000148","DOIUrl":"https://doi.org/10.1142/S1793617908000148","url":null,"abstract":"The electronic structures of Heusler-type Fe2VAl-based alloys, n-type thermoelectric alloys Fe2VAl1-zXz(X = Si, Ge) and p-type one Fe2(V1-yTiy)Al, have been investigated by photoelectron spectroscopy with use of synchrotron radiation as an excitation photon source. Observed valence-band spectra of Fe2VAl agree quite well with the predicted density of states with a sharp pseudogap across the Fermi energy EF. Small substitution in Fe2VAl1-zXz and Fe2(V1-yTiy)Al reveals a rigid-band-like energy shift of the valence band, although the observed shift is smaller than expected in the rigid band model. Further substitution causes the modification of the electronic structure near EF and the appearance of mid-pseudogap states. However, the dependence of the thermoelectric properties of these alloys on substitution can be qualitatively explained by the observed change in the electronic structure near EF.","PeriodicalId":166807,"journal":{"name":"Advances in Synchrotron Radiation","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114608284","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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