A Study of Point Defects in the B2-Phase Region of the Fe–Al system by Mössbauer Spectroscopy

2010 ◽  
Vol 163 ◽  
pp. 299-302 ◽  
Author(s):  
Magdalena Jabłońska ◽  
Aneta Hanc ◽  
Anna Szostak

In this work, we employed the Mössbauer spectroscopy in a study of point defect formation in intermetallic phases of the B2 structure from the Fe-Al system as a function of Al concentration. We present the values of the 57Fe isomer shift and quadruple splitting for the components describing the point defect in the local environment of a Mössbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe-AS) are determined. The results shown that an increase in Al content causes an increase in vacancy and Fe-AS

2013 ◽  
Vol 203-204 ◽  
pp. 343-346
Author(s):  
Aneta Hanc-Kuczkowska

In this work, the Mössbauer spectroscopy employed in a study of point defect formation in intermetallic phases of the B2 structure from the Fe-Al system as a function of Al concentration. We present the values of the 57Fe isomer shift and quadruple splitting for the components describing the point defect in the local environment of a Mössbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe-AS) are determined. The results shown that an increase in Al content causes an increase in vacancy and Fe-AS concentration.


2010 ◽  
Vol 636-637 ◽  
pp. 651-656
Author(s):  
Aneta Hanc ◽  
Jerzy Kansy

In this work, Mössbauer spectroscopy and X-ray powder diffraction (XRD) are used in a study of point defect formation in intermetallic phases of the B2 structure of the Fe-Al system as a function of Al concentration. The results are compared with the concentrations of point defect determined from positron annihilation data. In the Mössbauer effect, two types of samples are investigated: Fe-Al alloys with few additives obtained by induction melting and Al-rich metallic powders produced by the self-decomposition method and intensive grinding of high energy in the electro-magneto-mechanical mill. The work presents the values of the 57Fe isomer shift and quadruple splitting for the components describing the point defect in the local environment of a Mössbauer nuclide. The concentration of the Fe vacancies and Fe atoms substituting Al (Fe-AS) are determined. The results show that an increase in Al content causes an increase in vacancy and Fe-AS concentration.


Clay Minerals ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 591-606 ◽  
Author(s):  
E. De Grave ◽  
C. A. Barrero ◽  
G. M. Da Costa ◽  
R. E. Vandenberghe ◽  
E. Van San

AbstractThis paper presents various aspects, revealed by Mössbauer spectroscopy, of structural and magnetic properties of Al-substituted small-particle soil-related oxides. For goethite we focus on the relations between the hyperfine fields on the one hand, and crystallinity and Al content on the other. It is argued that these relations only provide a rough estimate of the Al content in natural samples. The ferrimagnetic-like behaviour reflected in the external-field Mössbauer spectra (4.2 K, 60 kOe) of certain Al goethites is presented. The spectra obtained for lepidocrocites are not spectacular, but confirmed that up to ∼10 at.% Al can be incorporated in the structure. Three differently-made series of hematites are considered. The Morin transition and spin structures in hematite are very sensitive to crystallinity and Al content, and probably to the presence of structural OH–. Integral low-energy electron Mössbauer spectroscopy on non-substituted samples indicates that the Morin-transition temperature in the surface layers (2 to 5 nm) is not significantly shifted from the bulk value. Measurements in extremely high magnetic fields (140 kOe) have shown that a spin-flip transition is induced in highly-substituted samples which exhibit no Morin transition in zero field. The use of external fields is crucial for the characterization and precise determination of the hyperfine parameters and site occupancies for maghemites, and for phase analyses of magnetic soils.


1997 ◽  
Vol 56 (11) ◽  
pp. 6371-6375 ◽  
Author(s):  
C. Pérez Vicente ◽  
J. L. Tirado ◽  
P. E. Lippens ◽  
J. C. Jumas

2004 ◽  
Vol 58 (27-28) ◽  
pp. 3432-3436 ◽  
Author(s):  
J.C. Waerenborgh ◽  
D.P. Rojas ◽  
A.L. Shaula ◽  
V.V. Kharton ◽  
F.M.B. Marques

1990 ◽  
Vol 56 (1-4) ◽  
pp. 1621-1626 ◽  
Author(s):  
D. Mo ◽  
G. L. Zhang ◽  
Z. N. Liang ◽  
L. Niesen

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 133-136 ◽  
Author(s):  
Paweł Stoch ◽  
Agata Stoch

Abstract 60P2O5-40Fe2O3 glass was synthesized and 57Fe Mössbauer spectroscopy study was presented. The main goal of the research was to investigate structural changes of local environment of iron ions during gradual crystallization of the glass. It was observed that some changes were evidenced at temperature of heat treatment higher than 400°C, above which content of tetrahedrally coordinated Fe3+ was increased in cost of octahedral sites. This led to formation of areas of nucleation of α-FePO4. Crystallization of α-Fe3(P2O7)2 and Fe2P2O7 was also observed.


2008 ◽  
Vol 114 (6) ◽  
pp. 1555-1562
Author(s):  
A. Hanc ◽  
J. Kansy ◽  
G. Dercz ◽  
L. Pająk ◽  
D. Oleszak ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document