Search

The sub-nanometer amplitudes of the samples vibrated with high frequencies were measured by 57Fe Mössbauer spectroscopy using a nuclear Bragg monochromator and focusing optics. The Mössbauer spectra of the vibrated single-line absorber showed comb-like absorption peaks, and the amplitudes of the absorbers were determined by the sideband intensities. We used the stainless-steel foil glued on the quartz crystal or the polyvinylidene fluoride (PVDF) film as samples. The mean value and the variance of the amplitude in sub-nanometer order were obtained for the irradiated area of 100 μm diameter in the sample. We could obtain the sub-nanometer amplitude with almost zero variance, using the 57Fe synchrotron Mössbauer source and focusing optics for the PVDF film. The resonant absorber vibrated with high frequency and amplitude without variance is useful for the control of gamma rays. This work will advance X-ray quantum optics and quantum technology applications using a single gamma photon. [ABSTRACT FROM AUTHOR]

The pressure dependence of the 151Eu isomer shift of EuH2 in the Pnma structure was evaluated under the pressure below 5 GPa by 151Eu energy-domain synchrotron-radiation-based Mössbauer spectroscopy. The isomer shift gradually increased as the pressure increased and its pressure dependence was understood by the simple linear relation with the inverse of the lattice volume of the hydrides. Furthermore, the isomer shifts of Eu hydride under hydrogen pressure and those of EuH2 under helium pressure did not show systematic difference. These results suggested that there was no or little hydrogen absorption after the synthesis of Pnma EuH2 in the pressure range up to 5 GPa. The linear relation between the isomer shift and the inverse of the volume in this initial hydride phase would be applied to the 151Eu Mössbauer study on other Eu hydride phases under higher hydrogen pressure to estimate the presence or absence of additional hydrogen absorption. [ABSTRACT FROM AUTHOR]

The pressure dependence of the 151Eu isomer shift of EuH2 in the Pnma structure was evaluated under the pressure below 5 GPa by 151Eu energy-domain synchrotron-radiation-based Mössbauer spectroscopy. The isomer shift gradually increased as the pressure increased and its pressure dependence was understood by the simple linear relation with the inverse of the lattice volume of the hydrides. Furthermore, the isomer shifts of Eu hydride under hydrogen pressure and those of EuH2 under helium pressure did not show systematic difference. These results suggested that there was no or little hydrogen absorption after the synthesis of Pnma EuH2 in the pressure range up to 5 GPa. The linear relation between the isomer shift and the inverse of the volume in this initial hydride phase would be applied to the 151Eu Mössbauer study on other Eu hydride phases under higher hydrogen pressure to estimate the presence or absence of additional hydrogen absorption. [ABSTRACT FROM AUTHOR]

We demonstrate a measurement system for synchrotron-radiation-based Mössbauer absorption spectra with 161Dy using the 25.7 keV nuclear first excited state. Mössbauer spectra of DyF3, Dy metal and DyPc2 (Pc = phthalocyaninato) were obtained and the parameters for the hyperfine structure of 161Dy nuclei in them were evaluated to demonstrate the feasibility of this method. Isomer shifts showed that Dy atoms in all of them are in trivalent state although those in Dy metal was in the region of trivalent metal region. The magnetic hyperfine field of Dy metal of 569 ± 1 T agreed with the literature of the Mössbauer experiments. That of DyPc2 of 489 ± 1 T was reasonable because the ground state of DyPc2 were in the state of Jz = ±13/2. Considering the highly penetrative nature of the 25.7 keV incident radiation, it will be straightforward to apply this method for the study of materials under various conditions such as high pressure, high magnetic fields, and reactive atmospheres. [ABSTRACT FROM AUTHOR]

149Sm synchrotron-radiation-based Mössbauer spectroscopy was performed in Sm-based intermetallics having a cubic crystal structure, Sm3Tr4Ge13, SmB6, SmBe13, and SmTr2Al20 (Tr = transition metals). In spite of the difference of the local structure around the Sm sites, the observed Mössbauer spectra consist of a single line at 300 K. On the other hand, Sm LIII-edge X-ray absorption spectra consist of two components, suggesting Sm2+ and Sm3+ states. Difference of the number of the spectral components between the Mössbauer spectroscopy and X-ray absorption spectroscopy is caused by the difference of the time window in the scattering process of these measurements. Correlation between the isomer shifts in the Mössbauer spectroscopy and average Sm valence states estimated from the X-ray absorption spectroscopy exhibits a linear correlation. [ABSTRACT FROM AUTHOR]