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Journal Articles

Effect of $$B$$-site randomness on the antiferroelectric/relaxor nature of the ground state; Diffuse and inelastic X-ray scattering study of Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_3$$

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

Physical Review B, 98(5), p.054106_1 - 054106_10, 2018/08

https://doi.org/10.1103/PhysRevB.98.054106
 Times Cited Count：3 Percentile：16.9(Materials Science, Multidisciplinary)

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

https://doi.org/10.3938/jkps.59.2509
 Times Cited Count：2 Percentile：20.43(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

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

https://doi.org/10.14723/tmrsj.34.19

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

https://doi.org/10.1103/PhysRevB.77.094136
 Times Cited Count：17 Percentile：57.06(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

XAFS study of relaxor Pb(In$$_{0.5}$$Nb$$_{0.5}$$)O$$_3$$

Yoneda, Yasuhiro; Yasuda, Naohiko*

Transactions of the Materials Research Society of Japan, 33(1), p.15 - 18, 2008/03

Pb $$L$$$$_{III}$$-edge absorption spectra of ordered and disordered Pb(In$$_{0.5}$$Nb$$_{0.5}$$)O$$_3$$ (PIN) were analyzed. The absorption edges of both the ordered and disordered PIN were shifted depending on the thermal condition of post-annealing. A clear edge shift was observed between the ordered and disordered PIN crystals. The local environments of the Pb atoms were different in these PIN crystals. This edge shift can be interpreted by introducing disarrangement of B-site atoms. Disordering of B-site atoms has not only an effect on the local bond distribution but also an effect on the long-range order crystal structure.

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

https://doi.org/10.1143/JPSJ.75.024606
 Times Cited Count：6 Percentile：42.19(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

Estimation methods of blood boron concentration and error evaluation during boron neutron capture therapy for malignant brain tumor

Shibata, Yasushi*; Yamamoto, Kazuyoshi; Matsumura, Akira*; Yamamoto, Tetsuya*; Hori, Naohiko; Kishi, Toshiaki; Kumada, Hiroaki; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Nakai, Kei*; et al.

JAERI-Research 2005-009, 41 Pages, 2005/03

JAERI-Research-2005-009.pdf:1.99MB

The measurement of neutron flux and boron concentration in the blood during medical irradiation is indispensable in order to evaluate the radiation in boron neutron capture therapy. It is, however, difficult to measure the blood boron concentration during neutron irradiation because access to the patient is limited. Therefore we prospectively investigated the predictability of blood boron concentrations using the data obtained at the first craniotomy after infusion of a low dosage of BSH. When the test could not be carried out, the blood boron concentration during irradiation was also predicted by using the 2-compartment model. If the final boron concentration after the end of the infusion is within 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%. If the final boron concentration at 6 or 9 hours after the end of infusion is out of 95% confidence interval of the prediction, proportional adjustment will reduce error and expected error after adjustment to around 12%.

Journal Articles

Defect-induced phase separation in relaxor Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_3$$ crystals

Yoneda, Yasuhiro; Matsumoto, Norimasa; Terauchi, Hikaru*; Yasuda, Naohiko*

Journal of Physics; Condensed Matter, 15(3), p.467 - 474, 2003/01

https://doi.org/10.1088/0953-8984/15/3/311
 Times Cited Count：6 Percentile：35.84(Physics, Condensed Matter)

Thermal properties of ordered and disordered Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_3$$ (PIN) single clystals were investigated. The defect-induced phase separation provided a good agreement of the instability of the relaxor nd antiferroelectric states of the PIN crystals.

Journal Articles

The Prediction of Boron concentrations in blood for patients of boron neutron capture therapy, 2

Shibata, Yasushi*; Matsumura, Akira*; Yamamoto, Tetsuya*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Nakai, Kei*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Hori, Naohiko; et al.

Research and Development in Neutron Capture Therapy, p.1055 - 1060, 2002/09

We prospectively investigated the predictability of blood boron concentrations using the data obtained at the first craniotomy after infusion of a low dose of sodium undecahydroclosododecaborate (BSH). Nine patients with malignant glial tumors underwent Boron neutron capture therapy (BNCT) at the Japan Atomic Energy Research Institute (JAERI) between 1995 and 2001. In 7 patients, 1g of BSH was infused before the first tumor removal and boron concentrations were determined using prompt gamma ray analysis (PGA). Then, 12 hours before BNCT, patients were infused at a dose of 100mg/kg BSH, and the boron concentrations were determined again. The boron biodistribution data showed a biexponential pharmacokinetic profile. If the final boron concentration at 6 or 9 hours after the end of the infusion is within the 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%.

Journal Articles

Optimization of intraoperative (IO)BNCT; Pre-irradiation surgical technique and 2-D dosimetry in surgical field

Yasuda, Susumu*; Yamamoto, Tetsuya*; Matsumura, Akira*; Shibata, Yasushi*; Akutsu, Hiroyoshi*; Matsushita, Akira*; Nakai, K.*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; et al.

Proceedings of 9th International Symposium on Neutron Capture Therapy for Cancer, p.171 - 172, 2000/10

no abstracts in English

Journal Articles

Prediction of boron concentration in blood from low dose infusion for the patients of BNCT at JAERI

Shibata, Yasushi*; Matsumura, Akira*; Yamamoto, Tetsuya*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Nakai, K.*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Hori, Naohiko; et al.

Proceedings of 9th International Symposium on Neutron Capture Therapy for Cancer, p.145 - 146, 2000/10

no abstracts in English

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

XANES study of Relaxor Pb(In$$_{0.5}$$Nb$$_{0.5}$$)O$$_3$$

Yoneda, Yasuhiro; Yasuda, Naohiko*; Mizuki, Junichiro

no journal, , 

no abstracts in English

Oral presentation

Phonon measurements of relaxor Pb(In$$_{1/2}$$Nb$$_{1/2}$$)O$$_{3}$$

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

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

19 (Records 1-19 displayed on this page)
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