Relationship between viscosity and acyl tail dynamics in lipid bilayers

Nagao, Michihiro*; Kelley, E. G.*; Faraone, A.*; Saito, Makina*; Yoda, Yoshitaka*; Kurokuzu, Masayuki*; Takata, Shinichi; Seto, Makoto*; Butler, P. D.*

Physical Review Letters, 127(7), p.078102_1 - 078102_7, 2021/08

https://doi.org/10.1103/PhysRevLett.127.078102

Development of Te synchrotron-radiation-based Mssbauer spectroscopy

Kurokuzu, Masayuki*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Saito, Makina*; Masuda, Ryo*; Mitsui, Takaya; Yoda, Yoshitaka*; Seto, Makoto*

Hyperfine Interactions, 226(1), p.687 - 691, 2014/04

https://doi.org/10.1007/s10751-013-0995-2

Synchrotron radiation-based Mssbauer spectra of Yb measured with internal conversion electrons

Masuda, Ryo*; Kobayashi, Yasuhiro*; Kitao, Shinji*; Kurokuzu, Masayuki*; Saito, Makina*; Yoda, Yoshitaka*; Mitsui, Takaya; Iga, Fumitoshi*; Seto, Makoto

Applied Physics Letters, 104(8), p.082411_1 - 082411_5, 2014/02

https://doi.org/10.1063/1.4866280

A detection system for synchrotron-radiation (SR)-based Mssbauer spectroscopy was developed to enhance the nuclear resonant scattering counting rate and thus increase the available nuclides. In the system, a windowless avalanche photodiode (APD) detector was combined with a vacuum cryostat to detect the internal conversion (IC) electrons and fluorescent X-rays accompanied by nuclear de-excitation. As a feasibility study, the SR-based Mssbauer spectrum using the 76.5 keV level of Yb was observed without Yb enrichment of the samples. The counting rate was five times higher than that of our previous system, and the spectrum was obtained within 10 h. This result shows that nuclear resonance events can be more efficiently detected by counting IC electrons for nuclides with high IC coefficients. Furthermore, the windowless detection system enables us to place the sample closer to the APD elements and is advantageous for nuclear resonant inelastic scattering measurements. Therefore, this detection system can not only increase the number of nuclides accessible in SR-based Mssbauer spectroscopy but also allows the nuclear resonant inelastic scattering measurements of small single crystals or enzymes with dilute probe nuclides that are difficult to measure with the previous detection system.

Fe nuclear resonant inelastic scattering of iron based superconductor, FeTeSe

Kurokuzu, Masayuki*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Saito, Makina*; Masuda, Ryo; Mitsui, Takaya; Yoda, Yoshitaka*; Seto, Makoto*

no journal, , 

FeTeSe consists of only the superconducting layer of iron and chalcogenides and is one of the simplest iron-based superconductor. We measured the nuclear resonant inelastic scattering by Fe in FeTeSe and FeTe, to observe the temperature dependence of their phonon density of states (PDOS); FeTeSe has the highest superconducting temperature (T) among FeTeSe and the non-superconducting FeTe is the base material of FeTeSe. The difference between the PDOS of FeTeSe at temperatures below and above T is unclear. This indicates the phonons are not the main contribution to the superconductivity. On the other hand, the PDOS of FeTe changes depending on temperature and this change is understood by the results of the structural phase transition.