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Mössbauer spectra and electronic properties of titanomagnetite
Author(s) -
Melzer K.,
Šimša Z.,
Łukasiak M.,
Suwalski J.
Publication year - 1987
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170220821
Subject(s) - mössbauer spectroscopy , delocalized electron , analytical chemistry (journal) , spinel , spectral line , mössbauer effect , electron , materials science , titanium , electrical resistivity and conductivity , electronic structure , crystallography , chemistry , physics , metallurgy , computational chemistry , organic chemistry , chromatography , quantum mechanics , astronomy
Several Mössbauer studies of Ti‐Fe spinels have been reported in the literature for x ≦ 0.8 (B ANERJEE et al.; V ANLEERBERGHE et al.) or for x ≦ 0.05 (U MEMURA et al.). B HADURI measured the Mössbauer spectra of the whole system (0 ≦ x ≦ 1) and suggested that Ti x Fe 3− x O 4 samples with x < 0.5 show the properties of delocalized electrons; whereas those with x > 0.6 may be regarded as n‐type semiconductors with localized electrons. We present measurements of electrical properties and Mössbauer spectra of synthetic Ti x Fe 3− x O 4 single crystals with x = 0; 0.24; 0.5; 0.72. It is seen that the electronic behaviour strongly depends on the content of titanium. At a composition of approximately x = 0.65 a transition from n‐ to p‐type of electrical conductivity occurs. 57 Fe Mössbauer data of the samples for different temperatures obtained of the spectrum computer analysis using a least squares fit program are given. The Mössbauer spectra below and above the Néel temperature demonstrate the distinct decrease in mobility of electrons in dependence on the Ti content. It is evident from the Mössbauer spectrum of the sample Ti 0.72 Fe 2.28 O 4 recorded above the Néel temperature that Titanium is incorporated into the spinel structure of this system only in a four valent state.