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Journal Articles

Quantitative micro-X-ray fluorescence scanning spectroscopy of wet sediment based on the X-ray absorption and emission theories; Its application to freshwater lake sedimentary sequences

Katsuta, Nagayoshi*; Takano, Masao*; Sano, Naomi; Tani, Yukinori*; Ochiai, Shinya*; Naito, Sayuri*; Murakami, Takuma*; Niwa, Masakazu; Kawakami, Shinichi*

Sedimentology, 66(6), p.2490 - 2510, 2019/10

 Times Cited Count:3 Percentile:44.04(Geology)

Micro-X-ray fluorescence (XRF) scanning spectroscopy of marine and lake sedimentary sequences can provide detailed paleoenvironmental records available through element intensities proxy data. However, problems for effects of interstitial pore water on the micro-XRF intensities have been pointed out so far because of direct measurement on the split wet sediment surfaces. In this study, new methods for the XRF corrections were developed by being considered with the micro-X-ray scanning spectroscopy.

Journal Articles

Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment

Ekawa, Hiroyuki; Ashikaga, Sakiko; Hasegawa, Shoichi; Hashimoto, Tadashi; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Kimbara, Shinji*; Nanamura, Takuya; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D02_1 - 021D02_11, 2019/02

 Times Cited Count:23 Percentile:84.13(Physics, Multidisciplinary)

Journal Articles

Trapping probability of strangeness via $$mathrm{Xi}^{-}$$ hyperon capture at rest in nuclear emulsion

Theint, A. M. M.*; Ekawa, Hiroyuki; Yoshida, Junya; 7 of others*

Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D01_1 - 021D01_10, 2019/02

 Times Cited Count:6 Percentile:48.53(Physics, Multidisciplinary)

Journal Articles

Charge identification of low-energy particles for double-strangeness nuclei in nuclear emulsion

Kimbara, Shinji*; Ekawa, Hiroyuki; Hayakawa, Shuhei; Yoshida, Junya; 12 of others*

Progress of Theoretical and Experimental Physics (Internet), 2019(1), p.011H01_1 - 011H01_9, 2019/01

 Times Cited Count:3 Percentile:37.12(Physics, Multidisciplinary)

A development has been achieved in the identification method of the charges 1 to 5 of nuclides from the decay of double hypernuclei to be uniquely recognized by their nuclear species. The method is basically the measurement of track volume by the widths, depths, and angles of tracks of exposed nuclei of $$^{1}$$H, $$^{4}$$He, $$^{7}$$Li, $$^{9}$$Be, and $$^{11}$$B in nuclear emulsion at Riken Projectile-fragment Separator of RIKEN Radioactive Isotope Beam Factory. After their calibration by $$alpha$$ particles, we obtained a quadric function to present a unified recognition of tracks with volume ratios of five nuclei to the $$alpha$$ particles. The function in the emulsion has been applied to a candidate event of a $$Xi$$ hypernucleus for identification of the production and decay processes. We succeeded in recognizing a daughter nuclear fragment of a single-$$Lambda$$ hypernucleus as $$^{6}$$He with a likelihood ratio of 0.9; the process was then uniquely identified as $$Xi$$$$^{-}$$ + $$^{14}$$N $$rightarrow$$ $$_{Lambda}$$$$^{9}$$Be + $$_{Lambda}$$$$^{5}$$He + $$n$$.

Journal Articles

Effect of B-site randomness on the antiferroelectric/relaxor nature of the ground state; Inelastic X-ray scattering study of Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$

Owada, Kenji; Fukuda, Tatsuo; Mizuki, Junichiro; Hirota, Kazuma*; Terauchi, Hikaru*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Owa, Hidehiro*; Yasuda, Naohiko*

Journal of the Korean Physical Society, 59(3), p.2509 - 2514, 2011/09

 Times Cited Count:2 Percentile:20.2(Physics, Multidisciplinary)

Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ (PIN) can be antiferroelectric (AFE), ferroelectric (FE) or a relaxor depending upon the perovskite B-site randomness. Orderd PIN (O-PIN, without B-site randomness) is supposed to be an ideal system of lead-based complex perovskite Pb(B'B'')O$$_{3}$$ and expected to give us a clear picture of the AFE/relaxor nature of the ground state by the B-site randomness. We studied the dynamics of O-PIN by inelastic X-ray scattering. The quasielastic (QE) scattering shows the critical slowing down and the transverse acoustic (TA) mode shows the softening towards $$T_{rm N}$$. On the other hand, the transverse optic (TO) mode shows the softening toward low temperature with no clear anomaly at $$T_{rm N}$$. These results represent that the antiferroelectric (AFE) phase transition is associated with the TA and the origin of the QE scattering, while ferroelectric correlation does exist behind the AFE ordering. The effect of B-site randomness is finally discussed on the basis of the results.

Journal Articles

High-pressure study of ScH$$_{3}$$; Raman, infrared, and visible absorption spectroscopy

Kume, Tetsuji*; Oura, Hiroyuki*; Takeichi, Tomoo*; Omura, Ayako*; Machida, Akihiko; Watanuki, Tetsu; Aoki, Katsutoshi; Sasaki, Shigeo*; Shimizu, Hiroyasu*; Takemura, Kenichi*

Physical Review B, 84(6), p.064132_1 - 064132_7, 2011/08

 Times Cited Count:18 Percentile:59.63(Materials Science, Multidisciplinary)

Raman, IR, and visible absorption spectra of scandium trihydride (ScH$$_{3}$$) have been measured at high pressures up to 50 GPa at room temperature. The structural and electronic phase transitions were investigated. Successive hcp-intermediate-fcc phase transitions took place at 25 and 46 GPa. It was suggested that the intermediate phase of ScH$$_{3}$$ has the same structure as that of YH$$_{3}$$. The energy gap of ScH$$_{3}$$ is 1.7 eV at the ambient condition and is closed around 50 GPa, at which the crystal structure transforms to fcc.

Journal Articles

Antiferroelectric correlation in relaxor Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ and ferroelectric correlation in antiferroelectric Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Owa, Hidehiro*; Yasuda, Naohiko*

Transactions of the Materials Research Society of Japan, 34(1), p.19 - 22, 2009/03

Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ (PIN) can be antiferroelectric (AFE), ferroelectric (FE) or a relaxor depending upon the perovskite B-site randomness. This is characterized by measurements of dielectric response, which shows behavior that is usually clearly in one of those three classes. In contrast, X-ray scattering studies suggest the presence of AFE correlation in the relaxor state and FE in AFE state. Weak phonon softening at zone boundary in relaxor state shows that the AFE correlation intrinsically exists in PIN, as does the corresponding elastic scattering at (${it h}$/2 ${it k}$/2 0), while weak diffuse scattering around 333 Bragg reflection appears in AFE state suggesting FE correlation. These results will support our previous speculation that the AFE and FE correlations coexist in PIN (K. Owada ${it et al}$., Phys, Rev. B${bf 77}$ 094136 (2008)). Such a coexistence or competition is widely seen in the perovskite relaxor and the coexistence of FE and AFE correlations is essential for generating relaxor state.

Journal Articles

Intrinsic ferroelectric instability in Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ revealed by changing B-site randomness; Inelastic X-ray scattering study

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Owa, Hidehiro*; Yasuda, Naohiko*

Physical Review B, 77(9), p.094136_1 - 094136_8, 2008/03

 Times Cited Count:17 Percentile:60.03(Materials Science, Multidisciplinary)

Antiferroelectric (AFE), ferroelectric (FE) or relaxor states can appear in Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ (PIN) depending upon the perovskite B-site randomness. We studied the effects of this randomness on the dynamics of PIN by high resolution inelastic X-ray scattering using ordered PIN (AFE) and disordered PIN (relaxor) single crystals. We have found a clear softening of a transverse optic mode at the $$Gamma$$ point in both the samples, indicating a robust and intrinsic ferroelectric instability regardless of the actual ground state. We interpret that AFE is stabilized only when In and Nb ions are spatially ordered enough to overwhelm the FE instability. As the B-site randomness becomes larger, AFE is suppressed and the hidden FE state starts appearing. Ultimately, the randomness begins to predominate over the development of FE regions and blocks a long range FE order, which we believe yields polar nanoregions resulting in relaxor behaviors.

Journal Articles

High-pressure study of YH$$_{3}$$ by Raman and visible absorption spectroscopy

Kume, Tetsuji*; Oura, Hiroyuki*; Sasaki, Shigeo*; Shimizu, Hiroyasu*; Omura, Ayako*; Machida, Akihiko; Watanuki, Tetsu; Aoki, Katsutoshi; Takemura, Kenichi*

Physical Review B, 76(2), p.024107_1 - 024107_5, 2007/07

 Times Cited Count:37 Percentile:78.76(Materials Science, Multidisciplinary)

Raman and visible absorption spectra of YH$$_{3}$$ were measured at high pressures, in order to clarify the structural and electronic phase transitions. The Raman results revealed the presence of an intermediate phase at 9-24 GPa between the low-pressure hexagonal and high-pressure fcc phases. The Y-framework structure and the positions of interstitial H atoms are changed on the transition to the intermediate phase. The results of the absorption measurements demonstrate that the optical band gap begins to close in response to the phase transition.

Journal Articles

Spatial distribution of the B-site inhomogeneity in an ${it as-grown}$ Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ single crystal studied by a complementary use of X-ray and neutron scatterings

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

Journal of the Physical Society of Japan, 75(2), p.024606_1 - 024606_6, 2006/12

 Times Cited Count:6 Percentile:41.88(Physics, Multidisciplinary)

Structural properties of ${it as-grown}$ Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ (PIN) single crystals at room temperature (RT) were investigated by X-ray and neutron scattering techniques, taking much account of the difference in the penetration depth and spatial resolution of X-rays and those of neutrons. A strong diffuse scattering was observed by X-ray while h/4, k/4, 0 superlattice reflections were found by neutron, indicating a relaxor state in the outer-layer of the crystal and an antiferroelectric (AFE) state in the bulk. The phonon dispersion was measured for the first time for the PIN series. Two transverse optic (TO1 and TO2) modes were clarified near the zone center though neither water-fall behavior nor folding of phonon branches was confirmed. We have thus concluded that a major part of the ${it as-grown}$ PIN crystal at RT is ferroelectric (FE). These results imply that the $$B$$-site chemical ordering, i.e. inhomogeneity, which controls the structural properties of PIN, is unevenly distributed throughout the crystal. We speculate that small AFE grains coexist with the FE matrix while the outer-layer is in a relaxor state in the ${it as-grown}$ PIN.

JAEA Reports

None

*

JNC TJ6400 2002-005, 41 Pages, 2003/03

JNC-TJ6400-2002-005.pdf:1.36MB

no abstracts in English

JAEA Reports

None

*

JNC TJ6400 2000-007, 48 Pages, 1999/03

JNC-TJ6400-2000-007.pdf:1.23MB

None

JAEA Reports

None

PNC TJ6622 97-001, 38 Pages, 1997/03

PNC-TJ6622-97-001.pdf:1.33MB

None

Oral presentation

X-ray and neutron scattering study of Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

no abstracts in English

Oral presentation

Fracture analysis determined from integrated analysis of core-description and BTV images; Example from the Late Cretaceous Toki Granite, central Japan

Dia, C.*; Takagi, Hisanori*; Kojima, Satoru*; Otani, Tomoyuki*; Amano, Kenji

no journal, , 

no abstracts in English

Oral presentation

Intrinsic ferroelectric instability in Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$; Inelastic X-ray scattering in control of the B-site randomness

Owada, Kenji; Hirota, Kazuma*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A.*; Mizuki, Junichiro; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$(PIN) varies among antiferroelectric (AFE), ferroelectric (FE) and relaxor states depending upon the perovskite B-site randomness. We studied the effects of this randomness on the dynamics of PIN by high resolution inelastic X-ray scattering using ordered PIN (AFE) and disordered PIN (relaxor) single crystals. We have found a clear softening of a transverse optic mode at the $$gamma$$ point in both the samples, indicating a robust and intrinsic ferroelectric instability regardless of the actual ground state. We interpret that AFE is stabilized only when In and Nb ions are spatially ordered enough to overwhelm the FE instability. As the B-site randomness becomes larger, AFE is suppressed and the FE ground state starts appearing. Ultimately, the randomness competes with the development of FE regions and blocks a long range FE order, which we believe yields polar nanoregions resulting in relaxor behaviors.

Oral presentation

Intrinsic ferroelectric instability in Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ revealed by changing B-site randomness; Inelastic X-ray scattering study

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

no abstracts in English

Oral presentation

Intrinsic ferroelectric instability in Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ revealed by changing B-site randomness

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ (PIN) varies among antiferroelectric (AFE), ferroelectric (FE) and relaxor states depending upon the perovskite B-site randomness. We studied the effects of this randomness on the dynamics of PIN by high resolution inelastic X-ray scattering using ordered PIN (AFE) and disordered PIN (relaxor) single crystals. We have found a clear softening of a transverse optic mode at the $$Gamma$$ point in both the samples, indicating a robust and intrinsic ferroelectric instability regardless of the actual ground state. We interpret that AFE is stabilized only when In and Nb ions are spatially ordered enough to overwhelm the FE instability. As the B-site randomness becomes larger, AFE is suppressed and the FE ground state starts appearing. Ultimately, the randomness competes with the development of FE regions and blocks a long range FE order, which we believe yields polar nanoregions resulting in relaxor behaviors.

Oral presentation

Ferroelectric and antiferroelectric correlations in antiferroelectric Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$ studied by X-ray diffraction

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

no abstracts in English

Oral presentation

Inelastic X-ray scattering study of Ordered-Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$

Owada, Kenji; Hirota, Kazuma*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

no journal, , 

no abstracts in English

28 (Records 1-20 displayed on this page)