High Pressure Collapse of Magnetism in Fe0.94O: Mössbauer Spectroscopy Beyond 100 GPa
| Autor: | Raymond Jeanloz, Moshe P. Pasternak, Xiaoyuan Li, Catherine McCammon, R. D. Taylor, Jeffrey H. Nguyen |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 79:5046-5049 |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.79.5046 |
| Popis: | First studies of M\"ossbauer spectroscopy to pressures above 100 GPa are reported. The magnetic state of ${\mathrm{Fe}}_{0.94}\mathrm{O}$ was investigated to 120 GPa at $T\ensuremath{\le}300\mathrm{K}$. At 300 K a diamagnetic low-spin (LS) state of ${\mathrm{Fe}}^{2+}$ is detected at 90 GPa; its abundance increases with $P$. The gap between the $^{5}T_{2g}$ high-spin ground state and the $^{1}A_{1g}$ LS excited state decreases with increasing $P$ and at 120 GPa the LS species, first observed at 70 K, is fully converted at $\ensuremath{\sim}450\mathrm{K}$. The magnetic collapse of ${\mathrm{Fe}}_{1\ensuremath{-}x}\mathrm{O}$ is an isochoric, second-order transition resulting from a gradual increase in the crystal-field with increasing pressure. |
| Databáze: | OpenAIRE |
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