Development of an energy-domain 57Fe-Mössbauer spectrometer using synchrotron radiation and its application to ultrahigh-pressure studies with a diamond anvil cell.
An energy-domain (57)Fe-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 (57)FeBO(3) single crystal near the Néel temperature and an X-ray focusing device. The developed spectrometer can filter the Doppler-shifted single-line (57)Fe-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 (57)Fe-Mössbauer spectrometer and its demonstrative applications including the newly discovered result of a pressure-induced magnetic phase transition of polycrystalline (57)Fe(3)BO(6) and an unknown high-pressure phase of Gd(57)Fe(2) 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.
Japan Atomic Energy Agency, Sayo-gun, Hyogo, Japan. taka@spring8.or.jp
Takaya
T
Mitsui
Naohisa
N
Hirao
Yasuo
Y
Ohishi
Ryo
R
Masuda
Yumiko
Y
Nakamura
Hirotoshi
H
Enoki
Kouji
K
Sakaki
Makoto
M
Seto