The influence of the semiconductor properties on the Mössbauer emission spectra of 57Co cobalt oxide

Harami, T.; Loock, J. F. J. Van; Huenges, Ernst; Fontcuberta, J.; Obradors, X.; Tejada, J.; Parak, F.

doi:10.1016/0022-3697(84)90117-3

Cited by 30 publications

(13 citation statements)

References 21 publications

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“…It can also be concluded that the 57Fe3+ daughter shows a much higher acceptor character than that corresponding t o the neutral cationic vacancies V&. This result is in agreement with the 57C01 experiments [3] in which it was concluded that the 57Fe3+ have a higher acceptor character than the neutral and singly ionized cationic vacancies [9, 101.…”

Section: Experimental and Resultssupporting

confidence: 89%

“…The Mossbauer spectra of TiCoO, consist of a single line whose isomer shift corresponds t o Fe+3. The results of the fits are given in Table 1 If the last Auger electron is trapped by the 57Fem3+ iron daughter, then a ferrous 57Fe2+ line appears in the Mossbauer spectra [2,3]. On other hand, when the last Auger electron is trapped by any other recombination centre existing in the semiconductor matrix and remains there longer than the Mossbauer lifetime (t = lO-'s), then the ferric line should appear in the Mossbauer spectra.…”

Section: Experimental and Resultsmentioning

confidence: 98%

“…The existence of the quadrupole interaction for both, ferrous and ferric, lines can be interpreted in terms of the local distortion appearing around the j7C02+ ions as a consequence of the different cation sizes and changes in the coordination number of the Co2+ ions in comparison with those of Cul+. The appearance of a single ferric line in the Mossbauer spectra of 57C02+Ti4+03 can be understood in the scope of our theoretical model explained above [3], in terms of the existence of acceptor levels in the energy gap of this oxide. Therefore, in the lack of a seniiconductor charact,erization of this oxide, we may anticipate that this double oxide will act as a p-type seniiconductor.…”

Section: Experimental and Resultsmentioning

confidence: 98%

“…The 57Fenz daugther can show very highly ionized states during a very short period of time (t < lO-'s) due t o the emission of Auger electrons [l]. As has been proposed very recently[3] the appearance of the j7Fe3+ charge state in the Mossbauer spectra is related to the electron recombination process occurring on a time scale shorter than lo-' s, for the last Auger electron.…”

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confidence: 98%

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Mössbauer emission studies of ⁵⁷Co‐doped ZnO, Cu₂O, and TiCoO₃

Roset

Fernández

Obradors

et al. 1986

Physica Status Solidi (b)

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J. ROSET et al. : Mossbauer Studies of 57Co-Doped ZnO, Cu,O, and TiCoO, 297 phys. stat. sol. (b) 134, 297 (1986)To-doped Mossbauer oxide sources are prepared a t different temperatures and oxidation pressures. The appearance of the S7Fe3+ anomalous charge state is related with the p-character of semiconductor oxide. Increasing the acceptor concentration increases the anomalous ferric line intensity in the Mossbauer spectra. The two location sites of 57C0 in the ZnO matrix correspond to substitutional and grain boundary sites, respectively. The n-character of ZnO oxide makes possible the appearance of the ferrous state in the corresponding Mossbauer spectra.Es werden drei Oxide als 57Co-Mo13bauer-Quellen untersucht. Nach den Experimenten kann man behaupten, daD das Auftreten der 57Fe3*-Linie im MoDbauer-Spektrum von Cu,O :Wo mit dem p-Charakter dieser Halbleiteroxide verbunden ist. Bei hoheren ,,Akzeptor"-Zustandskonzentrationen wird eine groI3ere Menge von Fe3+ im MoBbauer-Spektrum beobachtet. Dagegen wird keine Fe3f-Linie im MoDbauer-Spektrum des ZnO-Oxids beobachtet, was mit dem n-Halbleiter-Charakter dieser Oxide verbunden ist. Die 57Co-Kationen besetzen zwei verschiedene Platze in der ZnO-Matrix, die der Zn-Kationen und die Grenzplatze zwischen den Kornern.

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Section: Experimental and Resultssupporting

confidence: 89%

Section: Experimental and Resultsmentioning

confidence: 98%

Section: Experimental and Resultsmentioning

confidence: 98%

mentioning

confidence: 98%

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Mössbauer emission studies of ⁵⁷Co‐doped ZnO, Cu₂O, and TiCoO₃

Roset

Fernández

Obradors

et al. 1986

Physica Status Solidi (b)

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“…The autoradiolysis model [3] is based on the observation that for different Co(II) hydrates the amount of Fe 3+ species indicated by the Mössbauer spectra is proportional to the number of coordinated water molecules. A critical review of this model is given by Spiering et al [4], The model of competing acceptors, which was successfully applied for the aftereffects in cobalt(II) oxide [5], assumes virtually incomplete neutralization, i.e., the host material may contain stronger electron acceptors than the Fe 3+ ion, and thus Fe 3+ can be identified in the spectrum. In the case of some lowspin cobalt complexes, excited ligand field states with comparable lifetimes to that of the 57 Fe 14.4 keV nuclear level were also verified [4], It is noteworthy that the aliovalent charge states observed in the Mössbauer Table 1.…”

Section: Introductionmentioning

confidence: 99%

Emission Mössbauer Studies on Cobalt Carbonyl Complexes Labelled with ⁵⁷Co

et al. 1994

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Three different "Co-doped cobalt carbonyl complexes, NaCo (CO) 4 , Co 2 (CO) 8 , and CH 3 C(=0)Co(CO) 3 PPh 3 , representing a formal valence state of cobalt -1,0, and +1, respectively, were prepared and studied by emission Mössbauer spectroscopy. As a result of aftereffects of the EC decay of 57 Co, Fe 2+ and Fe 3+ states could be identified in the Mössbauer spectra with hardly any dependence on the initial valence state of cobalt. This observation is explained by assuming the fragmentation of these molecules as result of the electron loss caused by the Auger ionization of the nucleogenic 57 Fe atom.

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