The Translational, rotational, and phonon dynamics of water in ZrO/water nanofluid

Yoshida, Koji*; Sanada, Yusuke*; Yamaguchi, Toshio*; Matsuura, Masato*; Tamatsukuri, Hiromu; Uchiyama, Hiroshi*

Journal of Molecular Liquids, 366, p.120218_1 - 120218_9, 2022/11

https://doi.org/10.1016/j.molliq.2022.120218

Precise measurement of acoustic phonons in PrFeAsO

Fukuda, Tatsuo; Baron, A. Q. R.*; Uchiyama, Hiroshi*; Nakamura, Hiroki; Ishikado, Motoyuki*; Machida, Masahiko; Shamoto, Shinichi

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 3(2), p.290 - 293, 2015/07

http://doi.org/10.18957/rr.3.2.290

Phonon spectra of PrFeAsO via inelastic X-ray scattering

Fukuda, Tatsuo; Baron, A. Q. R.*; Nakamura, Hiroki; Shamoto, Shinichi; Ishikado, Motoyuki; Machida, Masahiko; Uchiyama, Hiroshi*; Iyo, Akira*; Kito, Hijiri*; Mizuki, Junichiro; et al.

Journal of the Physical Society of Japan, 80(Suppl.B), p.SB015_1 - SB015_4, 2011/01

https://doi.org/10.1143/JPSJS.80SB.SB015

We have investigated phonons of PrFeAsO using high-resolution inelastic X-ray scattering and calculations. Extensive measurements show that there are some changes in phonon spectra with temperature and/or doping. However, we compare our data with several calculations and find that the experimentally observed changes are much smaller than differences between the experiment. data and the calculations. Agreement is improved if magnetism is included in the calculations. However, still in disagreement even in the parent sample below T. We consider several modifications of the calculations. The best agreement is obtained from modifying the nonmagnetic calculation. by softening only the in-plane nearest-neighbor Fe-As force constant. Fluctuating magnetism may be a partial explanation for the failure of the calculations, but seems incomplete in the face of the similarity of the measured phonon response in all the systems investigated including those known to have static magnetism.

Anomalous T-dep. of the low energy peak in stripe ordered LSNO

Fukuda, Tatsuo; Ikeuchi, Kazuhiko; Baron, A.*; Tsutsui, Satoshi*; Uchiyama, Hiroshi*; Mizuki, Junichiro; Yamada, Kazuyoshi*

no journal, , 

no abstracts in English

IXS studies of the lattice dynamics in PrFeAsO

Fukuda, Tatsuo; Baron, A. Q. R.*; Shamoto, Shinichi; Uchiyama, Hiroshi*; Ishikado, Motoyuki; Nakamura, Hiroki; Machida, Masahiko; Mizuki, Junichiro; Arai, Masatoshi; Iyo, Akira*; et al.

no journal, , 

Recently discovered iron-arsenide new superconductor has attracted considerable attraction. Within a few months the transition temperature () exceeded 50 K in some related compounds, and the possible novel physics as well as higher- are expected. At the early stage, calculations of phonon properties appeared and suggested that the superconductivity in these materials are not phonon mediated. However, the experimental verification is crucial. We carried out inelastic X-ray scattering on some powder as well as single samples, and found pronounced softening of the Fe-As modes compared to LDA-based phonon calculations. However, further investigation on single crystals showed the spectra are found to agree much better with calculations of the magnetic parent material, which has orthorhombic symmetry, than those using a tetragonal structure like the real superconducting compounds.

Inelastic X-ray scattering studies of the phonon properties on iron-based new superconductors

Fukuda, Tatsuo; Baron, A. Q. R.*; Shamoto, Shinichi; Ishikado, Motoyuki; Nakamura, Hiroki; Machida, Masahiko; Uchiyama, Hiroshi*; Iyo, Akira*; Kito, Hijiri*; Mizuki, Junichiro; et al.

no journal, , 

Phonon properties on iron-based new superconductors

Fukuda, Tatsuo; Baron, A. Q. R.*; Shamoto, Shinichi; Ishikado, Motoyuki; Nakamura, Hiroki; Machida, Masahiko; Uchiyama, Hiroshi*; Iyo, Akira*; Kito, Hijiri*; Mizuki, Junichiro; et al.

no journal, , 

Temperature dependence of the lattice dynamics in PrFeAsO

Fukuda, Tatsuo; Baron, A. Q. R.*; Ishikado, Motoyuki; Shamoto, Shinichi; Nakamura, Hiroki; Machida, Masahiko; Uchiyama, Hiroshi*; Mizuki, Junichiro; Arai, Masatoshi; Iyo, Akira*; et al.

no journal, , 

no abstracts in English

Phonon density of state measurements of LaFeAs(O,F) using inelastic X-ray scattering

Fukuda, Tatsuo; Baron, A. Q. R.*; Shamoto, Shinichi; Uchiyama, Hiroshi*; Ishikado, Motoyuki; Nakamura, Hiroki; Machida, Masahiko; Mizuki, Junichiro; Arai, Masatoshi; Iyo, Akira*; et al.

no journal, , 

We have been investigating the phonon properties in "1111" Fe-based superconductors using inelastic X-ray scattering. In some phonon branches the phonon energy is softened compared to the first principles calculation, while the difference was found to become small by considering spin moment on Fe atoms in calculation. However, the carrier doping and/or temperature dependence in phonon properties are relatively small. Recently the magnetic excitation was found to be extremely reduced in the over-doped samples, where the electron fermi surface around M point is disappeared and the nesting with hole fermi surface around point is lost. In this compound the phonon dispersion is expected to be different from under-doped or parent materials, so we measured phonon density of states of over-doped PrFeAsO. We found small difference around 12 meV. However, the difference is very small and more precise investigations are necessary.

Effect of magnetism on phonon dispersion of SrFeAs via inelastic X-ray scattering

Murai, Naoki*; Fukuda, Tatsuo; Uchiyama, Hiroshi*; Tsutsui, Satoshi*; Ishikawa, Daisuke*; Kobayashi, Tatsuya*; Nakamura, Hiroki; Machida, Masahiko; Nakajima, Masamichi*; Miyasaka, Shigeki*; et al.

no journal, , 

no abstracts in English