Development of an energy‐domain 57Fe‐Mössbauer spectrometer using synchrotron radiation and its application to ultrahigh‐pressure studies with a diamond anvil cell |
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Authors: | Takaya Mitsui Naohisa Hirao Yasuo Ohishi Ryo Masuda Yumiko Nakamura Hirotoshi Enoki Kouji Sakaki Makoto Seto |
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Abstract: | An energy‐domain 57Fe‐Mössbauer spectrometer using synchrotron radiation (SR) with a diamond anvil cell (DAC) has been developed for ultrahigh‐pressure measurements. The main optical system consists of a single‐line pure nuclear Bragg reflection from an oscillating 57FeBO3 single crystal near the Néel temperature and an X‐ray focusing device. The developed spectrometer can filter the Doppler‐shifted single‐line 57Fe‐Mössbauer radiation with a narrow bandwidth of neV order from a broadband SR source. The focused incident X‐rays make it easy to measure a small specimen in the DAC. The present paper introduces the design and performance of the SR 57Fe‐Mössbauer spectrometer and its demonstrative applications including the newly discovered result of a pressure‐induced magnetic phase transition of polycrystalline 57Fe3BO6 and an unknown high‐pressure phase of Gd57Fe2 alloy placed in a DAC under high pressures up to 302 GPa. The achievement of Mössbauer spectroscopy in the multimegabar range is of particular interest to researchers studying the nature of the Earth's core. |
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Keywords: | nuclear Bragg scattering nuclear resonant scattering Mö ssbauer spectroscopy diamond anvil cell high pressure extreme conditions phase transition Fe3BO6 GdFe2 |
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