Chapter 9
Mössbauer Spectroscopic Studies
on Atomic Diffusion in Materials
Yutaka Yoshida
Abstract Atomic jumps within the lifetime of a Mössbauer nuclear probe are known
to cause a line broadening, which is directly connected to the diffusivity, as predicted
theoretically by Singwi and Sjölander in 1960. Many research groups applied and
further extended their theory for the studies of elementary jump processes of Fe atoms
in single crystals: They analyzed Mössbauer spectrum in terms of line broadening
and motional averaging as functions of temperature as well as crystal orientation. To
observe such dynamical behaviours, we developed specially designed experimental
set-ups such as a high-temperature Mössbauer furnace for laboratory, in-beam and
on-line Mössbauer set-ups for accelerator facilities. First of all, we will introduce such
measuring techniques suitable for homogeneous materials, explaining their unique
features in this chapter. Secondary, we present an imaging technique in Mössbauer
spectroscopy which is opening a new possibility to study diffusion processes with
a diffusion-length from μm to mm after diffusion annealing at high temperature.
This original method enables us to measure the diffusion profiles separately for
the different spectral components in the material containing a complex microstructure. As examples, we will explain the studies on Fe diffusion in single and multicrystalline Si materials using “Mössbauer spectroscopic microscope (MSM),” which
enables us to measure the diffusion profiles separately for different chemical states
with a spatial resolution of several micrometres. This new method provides a possibility to investigate a diffusion process by considering of the interactions and the
correlations between Fe impurities and lattice defects such as dislocations, grain
boundaries, and residual stresses in different grains of materials. Finally, we apply
this technique to investigate carbon diffusion and segregation processes in Fe-steel,
and the mapping images at different temperatures are obtained separately for the
spectral components that originated from carbon impurities.
Y. Yoshida (B)
Shizuoka Institute of Science and Technology, Fukuroi, Japan
e-mail: yoshida.yutaka@sist.ac.jp
© Springer Nature Singapore Pte Ltd. 2021
Y. Yoshida and G. Langouche (eds.), Modern Mössbauer Spectroscopy,
Topics in Applied Physics 137, https://doi.org/10.1007/978-981-15-9422-9_9
445
Mössbauer Spectroscopic Studies
on Atomic Diffusion in Materials
Yutaka Yoshida
Abstract Atomic jumps within the lifetime of a Mössbauer nuclear probe are known
to cause a line broadening, which is directly connected to the diffusivity, as predicted
theoretically by Singwi and Sjölander in 1960. Many research groups applied and
further extended their theory for the studies of elementary jump processes of Fe atoms
in single crystals: They analyzed Mössbauer spectrum in terms of line broadening
and motional averaging as functions of temperature as well as crystal orientation. To
observe such dynamical behaviours, we developed specially designed experimental
set-ups such as a high-temperature Mössbauer furnace for laboratory, in-beam and
on-line Mössbauer set-ups for accelerator facilities. First of all, we will introduce such
measuring techniques suitable for homogeneous materials, explaining their unique
features in this chapter. Secondary, we present an imaging technique in Mössbauer
spectroscopy which is opening a new possibility to study diffusion processes with
a diffusion-length from μm to mm after diffusion annealing at high temperature.
This original method enables us to measure the diffusion profiles separately for
the different spectral components in the material containing a complex microstructure. As examples, we will explain the studies on Fe diffusion in single and multicrystalline Si materials using “Mössbauer spectroscopic microscope (MSM),” which
enables us to measure the diffusion profiles separately for different chemical states
with a spatial resolution of several micrometres. This new method provides a possibility to investigate a diffusion process by considering of the interactions and the
correlations between Fe impurities and lattice defects such as dislocations, grain
boundaries, and residual stresses in different grains of materials. Finally, we apply
this technique to investigate carbon diffusion and segregation processes in Fe-steel,
and the mapping images at different temperatures are obtained separately for the
spectral components that originated from carbon impurities.
Y. Yoshida (B)
Shizuoka Institute of Science and Technology, Fukuroi, Japan
e-mail: yoshida.yutaka@sist.ac.jp
© Springer Nature Singapore Pte Ltd. 2021
Y. Yoshida and G. Langouche (eds.), Modern Mössbauer Spectroscopy,
Topics in Applied Physics 137, https://doi.org/10.1007/978-981-15-9422-9_9
445