Conversion Electron Mossbauer Spectroscopy

Spijkerman, J. J.

doi:10.1007/978-1-4615-9002-6_5

Cited by 27 publications

(8 citation statements)

References 11 publications

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“…For SrFeO,, where the Fe atom in the cubic octahedral environment of the oxygen atoms is expected in 3d4 configuration, one has [lo] 6,, M 0.3 mm/s (corrected for reference to our standard), while for SrTiO, doped with iron, although a charge-compensating oxygen vacancy is present, one has [ll] 6,, w 0.6 mm/s for the Fe5' atom in the 3d5 high-spin ferric state. For the 3d6 configuration the expected value for a , , is at least of the order of 1.3 to 1.4 (mm/s) [9], as observed for instance in the FeCl, octahedra [IZ]. The analysis of the quadrupole splittings in Fig.…”

Section: Analysis Of the Data And Discussionmentioning

confidence: 65%

Mössbauer and Conductivity Study of Ferroelastic Ferric Molybdate

Orlandi¹,

Magistris

Rigamonti³

1982

phys. stat. sol. (a)

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The properties of ferroelastic ferric molybdate Fe2(MoO4)3 are investigated by Fe57‐Mössbauer and conductivity measurements. Center shifts, recoil‐free fractions, and quadrupole splitting are measured in the temperature range 77 to 800 K. The analysis of the isomer shifts and of the quadrupole interaction corroborates the assignment of a high‐spin 3d5 state. The temperature dependence of the second order Doppler shift, in the light of an Einstein model for the optical modes, yields θE ≈ 830 K, while from the recoil‐free fraction a Debye temperature around 313 K is inferred. The quadrupole splitting is about 0.2 mm/s at 77 K and decreases slightly on heating towards the ferroelastic transition. For T ⪆ 700 K the lines exhibit an anomalous broadening, which increases with the time. The conductivity measurements suggest that the extra‐broadening is related to oxygen vacancies, which induce a distribution of the electric field gradients at the iron site. The possible sources for the intrinsic field gradient and its temperature dependence are discussed.

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Section: Analysis Of the Data And Discussionmentioning

confidence: 65%

Mössbauer and Conductivity Study of Ferroelastic Ferric Molybdate

Orlandi¹,

Magistris

Rigamonti³

1982

phys. stat. sol. (a)

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“…In recent years, there has been much interest in the application of electron reemission Mossbauer (ERM) spectroscopy to the study of thin surface layers (1)(2)(3)(4)(5)(6)(7)(8).…”

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confidence: 99%

Electron Reemission Mossbauer Study of Tinplate

Huffman¹,

Dunmyre²

1978

J. Electrochem. Soc.

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Electron reemission Mossbauer (ERM) studies using the Sn 119 Mossbauer isotope have been made on a series of tinplate samples with tin coatings ranging from 0.1 to 1.0 lb/bb (2.24 to 22.4 g/m2). With a recently developed theory of ERM spectroscopy, the ERM spectra could be analyzed to determine the thickness of the oxide (SnO2), metallic Sn, and alloy (FeSn2) layers on the tinplate samples. The resulting thicknesses were found to be in good agreement with the nominal coating weights and, for several samples, with the metal and alloy thicknesses determined by standard stripping techniques. The ERM method is shown to be very sensitive to thin tin oxide layers ranging from a few monolayers to several hundred angstroms thick.In recent years, there has been much interest in the application of electron reemission Mossbauer (ERM) spectroscopy to the study of thin surface layers (1-8).In this technique, Mossbauer spectra are obtained by detecting the relatively low energy (typically ,-,1 to 20 keV) internal conversion and Auger electrons which are reemitted on deexcitation of Mossbauer nuclei following resonant absorption of recoilless Mossbauer gamma rays. Because these low energy electrons have relatively small escape distances (typically ,~100-10,000A), the bulk of the signal detected in an ERM experiment arises from the surface layers of the sample.In a recent publication by one of the authors (7), reasonably simple analytic expressions were derived relating the ERM spectra obtained from multilayer surface films to the thicknesses of the various layers. This theory permits, for the first time, quantitative interpretation of ERM spectra; it has been initially tested and found to give reasonably accurate results in an ERM study of the oxidation of metallic Fe in oxygen at temperatures up to 500~ (8).Although most previous ERM studies have utilized the Fe 57 nucleus, the Sn 119 nucleus also has excellent NIossbauer properties and is well suited to the ERM technique. The properties of Sn t19 of most interest with regard to ERM spectroscopy have been summarized in a recent paper by Yagnik, Masak, and Collins (3). The internal conversion and Auger electrons emitted on deexcitation of the Sn 119 nuclei have energies of 20 and 3 keV, respectively. Following resonant Mossbauer absorption of the recoilless 23.8-keV gamma rays emitted by Sn 119m nuclei in a suitable radioactive source, 84% of the absorbing Sn 119 nuclei in the sample deexcite themselves by reemission of internal conversion electrons, and 89% of these internal conversion electrons are followed by Auger electrons. Therefore, for every one hundred 23.8 keV gamma rays absorbed in the sample, eighty-four 20 keV internal conversion and seventy-five 3 keV Auger electrons are reemitted. Those electrons that escape from the sample can be detected and used to obtain an ERM spectrum.As is discussed in more detail later, the energies of these electrons are such that the bulk of the Sn 119 ERM signal arises from approximately the top 10,000A of the sample. This is precisely...

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“…CEMS and re-emitted -BMS 22,23 were carried out at room temperature. The spectra were taken using a 57 Co/Rh source.…”

Section: Methodsmentioning

confidence: 99%

Changes in austenitic steel surface induced by thermal and implantation treatments studied by Mössbauer spectroscopy

Jirásková

Schneeweiss

Blawert

2006

Surface & Interface Analysis

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The surface properties of austenitic (fcc) stainless steel samples in the as-prepared and implanted states were studied. The surface modification was done by plasma immersion ion implantation in methane. This process, done at a temperature of 400°C in a short time of 3 h, facilitates the enrichment of the steel surface by a higher carbon content. It reaches about 7 at% C in the top surface layers (∼500 nm) and decreases to the nominal value at approximately 10 µm.The thermal annealing treatments of the as-prepared and implanted samples, done at temperatures of 300-500°C and in time steps of 2-4-8-16-32 h, yielded changes in the elemental distribution and phase composition, which could be followed in the top surface layers of approximately 300 nm using conversion electron Mössbauer spectroscopy (CEMS) and for a surface depth down to 30 µm, by g-ray Mössbauer spectroscopy in the scattering geometry (g-BMS). Complementary results were obtained from glancing-angle X-ray diffraction.

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Conversion Electron Mossbauer Spectroscopy

Cited by 27 publications

References 11 publications

Mössbauer and Conductivity Study of Ferroelastic Ferric Molybdate

Mössbauer and Conductivity Study of Ferroelastic Ferric Molybdate

Electron Reemission Mossbauer Study of Tinplate

Changes in austenitic steel surface induced by thermal and implantation treatments studied by Mössbauer spectroscopy

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