LAP Lambert Academic Publishing ( 26.07.2012 )
€ 79,00
High pressure and variable temperature studies of synthetic FeS and Fe7S8 as well as natural FeTiO3 have been carried out in a diamond anvil cell. FeS in the low-pressure less than ~7 GPa has thermally activated charge carriers and a high-spin electronic configuration, whereas monoclinic-FeS above ~7 GPa adopts a magnetically quenched low-spin state and non-metallic behaviour associated with the filled valence band. By contrast Fe7S8 is magnetic and metallic below ~5 GPa and diamagnetic metallic above this pressure. The Fe3+/Fe2+ ratio in natural ilmenite samples shows rapid increase under pressure from ambient up to ~2 GPa, as deduced from 57Fe Mössbauer pressure studies. Pressure induced intervalence charge transfer away from the ferrous sites, conceivably across regions of octahedra, to the empty 3d manifold of the Ti4+ cation in an adjacent face-sharing layer along the c-axis may account for the change in the Fe3+/Fe2+ ratio. This is the first heteronuclear intervalence charge transfer observed by high-pressure Mössbauer study.
Kitap detayları: |
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ISBN-13: |
978-3-659-10266-0 |
ISBN-10: |
3659102660 |
EAN: |
9783659102660 |
Kitabın dili: |
English |
Yazar: |
Takele Seda |
Sayfa sayısı: |
216 |
Yayın tarihi: |
26.07.2012 |
Kategori: |
Yer bilimleri |