Journal article
New constraints on the melting temperature and phase stability of shocked iron up to 270 GPa probed by ultrafast x-ray absorption spectroscopy
- Abstract:
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Studying the properties and phase diagram of iron at high-pressure and high-temperature conditions has relevant implications for Earth’s inner structure and dynamics and the temperature of the inner core boundary (ICB) at 330 GPa. Also, a hexagonal-closed packed to body-centered cubic (bcc) phase transition has been predicted by many theoretical works but observed only in a few experiments. The recent coupling of high-power laser with advanced x-ray sources from synchrotrons allows for novel approaches to address these issues. Here, we present a study on shock compressed iron up to 270 GPa and 5800 K probed by single-pulse (100 ps FWHM) x-ray absorption spectroscopy (XAS). Based on the analysis of the XAS spectra, we provide structural identification and bulk temperature measurements along the Hugoniot up to the melting. These results rule out the predicted transition to a high-temperature bcc phase and allow one to discriminate among existing equations of state models and melting curves. In particular, we report the first bulk temperature measurement in shock compressed iron on the melting plateau at 240(20) GPa and 5345(600) K. The melting curve resulting from our work extrapolates to a temperature of 6202(514) K at 330 GPa and represents a refined upper bound for the ICB temperature.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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- Files:
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(Preview, Version of record, pdf, 711.9KB, Terms of use)
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- Publisher copy:
- 10.1103/physrevlett.133.254101
Authors
- Publisher:
- American Physical Society
- Journal:
- Physical Review Letters More from this journal
- Volume:
- 133
- Issue:
- 25
- Article number:
- 254101
- Publication date:
- 2024-12-18
- Acceptance date:
- 2024-09-13
- DOI:
- EISSN:
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1079-7114
- ISSN:
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0031-9007
- Language:
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English
- Pubs id:
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2071844
- Local pid:
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pubs:2071844
- Deposit date:
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2024-12-31
- ARK identifier:
Terms of use
- Copyright holder:
- Balugani et al
- Copyright date:
- 2024
- Rights statement:
- ©2024 The Authors. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
- Licence:
- CC Attribution (CC BY)
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