Effect of -site randomness on the antiferroelectric/relaxor nature of the ground state; Diffuse and inelastic X-ray scattering study of Pb(InNb)O

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

Antiferroelectric correlation in relaxor Pb(InNb)O and ferroelectric correlation in antiferroelectric Pb(InNb)O

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(InNb)O (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 (/2 /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 ., Phys, Rev. B 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.

Spatial distribution of the B-site inhomogeneity in an Pb(InNb)O 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

Structural properties of Pb(InNb)O (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 PIN crystal at RT is ferroelectric (FE). These results imply that the -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 PIN.

RHEED observation of BaTiO thin films grown by MBE

Yoneda, Yasuhiro; Sakaue, Kiyoshi*; Terauchi, Hikaru*

Surface Science, 529(3), p.283 - 287, 2003/04

https://doi.org/10.1016/S0039-6028(03)00361-3

Ferroelectric BaTiO thin filmwith a thickness of 10ML were epitaxally grown on SrTiO (001) substrate by very slow deposition using MBE. The investigation were carried out by two growth methods: (i) codeposition and (ii) alternate deposition. In-situ observation of RHEED confirmed that an epitaxial cube-on-cube structure was prepared. After the deposition, X-ray diffraction measurements were carried out. The 10-ML-thick BaTiO films were highly -axis oriented single crystals with good film quality.

Dielectric investigation of [(SrTiO)(BaTiO)] multilayer capacitor

Yoneda, Yasuhiro; Sakaue, Kiyoshi*; Terauchi, Hikaru*

Japanese Journal of Applied Physics, Part 1, 40(12), p.6888 - 6892, 2001/12

https://doi.org/10.1143/JJAP.40.6888

no abstracts in English

The Phase transition of BaTiO thin film on Pt/MgO substrate

Yoneda, Yasuhiro; Sakaue, Kiyoshi*; Terauchi, Hikaru*

Journal of Physics; Condensed Matter, 12(39), p.8523 - 8529, 2000/10

https://doi.org/10.1088/0953-8984/12/39/314

no abstracts in English

High energy XAFS study of Sm: K-edge in SmFeNx

Kasatani, Hirofumi*; Omura, Masashi*; Yokoyama, Katsumi*; Kobayashi, Kurima*; Nishihata, Yasuo; Yagi, Kenichiro*; Terauchi, Hikaru*

Japanese Journal of Applied Physics, 38(Suppl.38-1), p.433 - 435, 1999/06

https://doi.org/10.1143/JJAP.38.433

High energy XAFS studies of Sm: K-edge in Sm2Fe17Nx with x = 0.0, <= 0.1, 0.5, 2.0 and 3.0 were carried out at room temperature in order to clarify the relation between the local structure around the Sm-atom and the change of the magnetic property due to the absorption of nitrogen atom. In the XANES region, we firstly found the change of Sm electron state by nitriding because of the change of the shape in the absorption edge junp. In the result of the EXAFS spectra, we confirmed that the Sm-Fe distance was expanded monotonously due to the absorption of N-atom.

Structural characterization of BaTiO thin films grown by molecular beam epitaxy

Yoneda, Yasuhiro*; ; Sakaue, Kiyoshi*; Terauchi, Hikaru*; ;

Journal of Applied Physics, 83(5), p.2458 - 2461, 1998/03

https://doi.org/10.1063/1.367006

no abstracts in English

X-ray diffraction of SrTiO/BaTiO multilayer films

Yoneda, Yasuhiro*; ; Sakaue, Kiyoshi*; Terauchi, Hikaru*

Journal of the Korean Physical Society, 32, p.S1636 - S1638, 1998/02

no abstracts in English

Intrinsic ferroelectric instability in Pb(InNb)O 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(InNb)O (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 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.