Project 3 Project Research on Advances in Isotope-Specific Studies Using Muti-Element Mössbauer Spectroscopy (R4P3)

概要

I-1.

PROJECT RESEARCHES
Project 3

- 32 -

PR3

Project Research on Advances in Isotope-Specific Studies Using Muti-Element
Mössbauer Spectroscopy

M. Seto
Institute for Integrated Radiation and Nuclear Science,
Kyoto University
OBJECTIVES OF RESEARCH PROJECT:
Mössbauer spectroscopy is effective to extract several
information such as electronic states for a specific isotope. The objective of this project research is to progress
the investigation in the frontier of the materials science
and the development of advanced experimental methods
by using multi-element Mössbauer spectroscopy. Promotion of variety of Mössbauer isotope provides more useful and valuable methods in modern materials science
even for complicated systems.
In this project research, each group performed their research by specific isotopes:
57
Fe in R4P3-1, R4P3-2, R4P3-3, R4P3-4, R4P3-5,
R4P3-6
61
Ni in R4P3-7
197
Au in R4P3-8, R4P3-9
Other developments in R4P3-10, R4P3-11
R4P3-2(H. Fujii) was not performed this year.
MAIN SUBJECTS AND RESULTS OF THIS REPORT:
Main subjects and results are as follows:
(R4P3-1, K. Shinoda) Intensity tensor of Fe2+ in the
M1 Site of diopside by single crystal Mössbauer spectroscopy
K. Shinoda et al. successfully characterized the intensity tensor of quadrupole doublet of diopside, which is
Ca-rich and Fe-poor pyroxene, in a natural mineral by
Mössbauer microspectrometer.
(R4P3-3, I. Mashino) Electrical conductivity and the
iron valence state of silicate glasses up to Mbar pressures
I. Mashino et al. investigated Fe-bearing enstatite
glasses with variable amounts of iron components. The
Mössbauer spectroscopy at room and low temperatures
is used to determine the composition ratio and of Fe2+
and Fe3+components.
(R4P3-4, M. Tabuchi) Change in Fe valence state of
Fe and Ni substituted Li2MnO3 positive electrode material during different synthetic method by 57Fe Mössbauer spectroscopy
M. Tabuchi et al. performed 57Fe Mössbauer spectroscopy for several samples of Fe and Ni substituted
Li2MnO3 electrode materials with different preparation
method to improve the electro-chemical performance as
positive electrodes in Li-ion batteries.

R4P3
- 33 -

(R4P3-5, Y. Kamihara) Research on magnetism and
electronic phase in a H-doped iron-based superconductor
Y. Kamihara et al. prepared iron-based superconductors, H-doped SmFeAsO by high-temperature and
high-pressure synthesis and evaluated magnetic properties to investigate the mechanism of superconducting
electron pair formation and destruction. The Mössbauer
spectroscopy will be performed for this evaluated samples.
(R4P3-6, K. Yonezu) Experimental Preliminary Approach on the Precipitation Mechanism of Banded Iron
Formation (BIF): Part 2
K. Yonezu et al. performed 57Fe Mössbauer Spectroscopy of silica scales from operating geothermal
power plant to understand the banded iron formation
mechanism of chemically precipitated sedimentary
rock at Precambrian age.
(R4P3-7, T. Kitazawa) 61Ni Mössbauer Spectroscopy
for Hofmann-type Supramolecular Bridging Cyanide
Complexes
K. Kitase et al. synthesized three Hofmann-type
Fe-and Ni-contained coordination polymer and investigated them by 61Ni Mössbauer spectroscopy to evaluate the Ni environments in these compounds.
(R4P3-8, H. Ohashi) Chemical species for precursor
of supported gold cluster catalysts presumed from Recoil-free fraction in 197Au Mössbauer Spectroscopy
H. Ohashi et al. investigated precursor of supported
Au cluster and presumed chemical species of the precursor as an analogous complex of [Au(SH)2]- by 197Au
Mössbauer Spectroscopy.
(R4P3-9, Y. Kobayashi) Recoilless Fraction on 197Au
Mössbauer Spectroscopy(2)
Y. Kobayashi et al. investigated the evaluation method of the Debye temperature by measuring temperature
dependence of Mössbauer spectra for several Au compounds.
(R4P3-10, R. Masuda) EuS property as the energy
standard material at 151Eu Mössbauer spectroscopy
R. Masuda et al. evaluated the temperature dependence of the isomer shifts of EuS as a Eu2+ standard material for 151Eu Mössbauer spectroscopy.
(R4P3-11, S. Kitao) Development of 119Sn Mössbauer
Source
S. Kitao et al. have attempted to produce a 119Sn
Mössbauer source by using CaSnO3 compounds in
long-term neutron irradiation.

PR3-1

Intensity tensor for Fe2+ at the M1 site of diopside by single crystal Mössbauer spectroscopy

K. Shinoda1, D. Takagi1, Y. Kobayashi2
1

Department of Geosciences, Graduate School of Science, Osaka Metropolitan University
2
Institute for Integrated Radiation and Nuclear Science,
Kyoto University
INTRODUCTION: Pyroxene is a major rock-forming
mineral and a typical multi-site solid solution. Common
chemical formula of natural pyroxene is (Ca, Fe, Mg)2 Si2
O6. Occupying sites of divalent cations are the M1 and M2
sites. In pyroxene, Fe2+ in M1, Fe2+ in M2 and Fe3+ in M1
sites are possible. Fukuyama et al. (2022) emphasized that
the intensity tensor for Fe2+ at the M sites of pyroxene is
very important for analyzing Mössbauer spectra of singlecrystal pyroxene thin sections, because intensities of a
quadrupole doublet of a thin section as a single crystal are
asymmetric and vary depending on the angle between the
direction of incident g-rays and the crystallographic orientation. Intensity of quadrupole doublet (Ih / Itotal ) means a
ratio between area of the peak of the higher energy (Ih) and
total area of the doublet (Itotal= Ih + Il) (sum of Ih and area
of the lower energy (Il)). Intensity can be calculated from
the intensity tensor. Intensity tensors of Ca-rich and Ferich pyroxenes (augite and hedenbergite) were revealed by
Fukuyama (2022) [1]. However, Intensity tensor of diopside, that is Ca-rich and Fe-poor pyroxene, was not measured. In this study, intensity tensor for Fe2+ at the M1 site
of diopside was measured to confirm compositional dependence of the intensity tensor for Fe2+ at the M1 site in
Ca-rich pyroxene by single crystal Mössbauer spectroscopy.
EXPERIMENTS and RESULTS: Single crystals of diopside from Horado, Seki, Gifu prefecture, Japan were
used for this study. Chemical analyses of the diopside indicates
the
formula
(Ca0.97Fe0.06Mg0.94)S1.97
(Si1.99Al0.03)S2.02O6 by EDS. The molar contents of Mg and
Ca were 0.94 and 0.97, respectively. The results suggest
that Ca ions almost fully occupy the M2 sites and that the
Mg ions are not sufficient to occupy the M1 sites. Therefore, the major part of the Fe2+ ions occupy the M1 sites.
Three crystallographically oriented thin sections perpendicular to a, b and c were prepared by measuring X-ray
diffraction using Laue and precession cameras. Eight
Mössabuer spectra of oriented thin sections were measured.
In this study, Cartesian coordinate (X Y Z) is set as X//c*,
Y//a, Z//b, where c* are reciprocal lattice vectors of diopside. Mössbauer measurements were carried out in transmission mode on a constant acceleration spectrometer with
an Si-PIN semiconductor detector (XR-100CR, AMPTEK

Inc.) and multi-channel analyzer of 1024 channels. A
3.7GBq 57Co/Rh of 4mmf in diameter was used as g-ray
source. An 57Fe-enriched iron foil was used as velocity calibrant. The two symmetric spectra were folded and velocity range was ± 4mm/s. Thickness corrections of raw spectra were not done.

Fig.1. Mössbauer spectrum of diopside measured under
g-ray parallel to the a-axis.
Fig.1 shows Mössbauer spectrum of diopside measured
under incident g-ray parallel to a-axis. A doublet due to
Fe2+ in M1 site of diopside was observed. Averages of isomer shift (d ), Q-splitting (D ), and line width (G ) were
1.176(2) 1.919(4) and 0.310(4) mm/s, respectively. From
eight sets of intensity of quadrupole doublet, Four components (IXX, IYY, IZZ, IXY) of the intensity tensor of Fe2+ in the
M1 site of diopside are obtained as 0.328(7), 0.480(5),
0.692(12) and 0.050(15).
DISSCUSSION: The four components (IXX, IYY, IZZ, IXY)
of this study were compared with those of Ca-rich pyroxenes of different chemical compositions in Fukuyama et al.
(2022) [2]. According to Fukuyama et al. (2022), the intensity tensor due to Fe2+ at the M1 sites of diopside,
hedenbergite, and augite is dependent on the Wo content,
but independent of the Fs content. This result suggests that
components of the intensity tensor due to Fe2+ at M sites in
Ca-Mg-Fe pyroxene minerals that contain equal Wo and
different Fs components are almost constant.
REFERENCES
[1] Fukuyama., Master thesis, Osaka City Univ. (2020).
[2] D. Fukuyama et al., J. Mineral. Petrol. Sci., 117(1)
(2022) 220506.

R4P3-1
- 34 -

PR3-2

Electrical conductivity and the iron valence state of silicate glasses up to Mbar pressures

I. Mashino, T. Yoshino, S. Kitao1, T. Mitsui2, R. Masuda3,
M. Seto1
Institute for Planetary Materials, Okayama University
1
Institute for Integrated Radiation and Nuclear Science,
Kyoto University
2
Synchrotron Radiation Research Center, Kansai Photon
Science Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology
3
Graduate School of Science and Technology, Hirosaki
University

In-situ high-pressure synchrotron Mössbauer spectroscopic experiments and electrical conductivity measurements have been performed for the Fe-bearing enstatite
glasses in a diamond anvil cell. We observed the trend
changes in the pressure dependence of electrical conductivity and also the shape changes in Mössbauer spectra at
around 80-100 GPa. We are now discussing the obtained
results and then geophysical implications.
Table 1. Fitting results of the conventional Mössbauer
spectra of Fe-enstatite glasses at ambient pressure.

INTRODUCTION: The existance of gravitationally
stabilized melts at the bottom of the Earth’s mantle has
been proposed because a density crossover between melts
and crystals is expected to occur. However, whether the
crossover occurs in the lower mantle or not strongly depends on the chemical composition of both the melt and
crystals. ...