Local and electronic structures of BaTiO/KNbO nanocomposite particles

Yoneda, Yasuhiro; Kobayashi, Toru; Tsuji, Takuya; Shibata, Goro; Takeda, Yukiharu*; Saito, Yuji; Khanal, G. P.*; Fujii, Ichiro*; Ueno, Shintaro*; Sato, Yukio*; et al.

Japanese Journal of Applied Physics, 64(8), p.08SP07_1 - 08SP07_8, 2025/08

https://doi.org/10.35848/1347-4065/adf4f1

It has become possible to synthesize high-quality composite nanoparticles in which a different material is grown on the surface of nanoparticle crystals. To evaluate such nanostructures, it is effective to combine different evaluation methods at various scales. We performed various structural and electronic state evaluations of BaTiO/KNbO nanocomposite particles using synchrotron radiation. From the structural evaluation, it was confirmed that the nanocomposite particles have a core of 100 nm of BaTiO covered with 20 nm of KNbO. The O-K absorption edge spectrum of the outermost surface KNbO was different from that of the bulk and nanoparticles, and it was found that the chemical bonding state changes when KNbO is made into composite particles.

Dielectric studies on the phase transitions of {(NH)H(SO)}{ND)D(SO)} system; Ferroelectricity in (NH)H(SO)

; ;

Journal of the Physical Society of Japan, 49(2), p.593 - 598, 1980/00

https://doi.org/10.1143/JPSJ.49.593

no abstracts in English

Synthesis and solid solutionaization of nanoparticles of barium titanate, barium zirconate, and calcium titanate

Saito, Junichi; Matsuo, Naoki*; Kiba, Kazumasa*; Kudo, Junki*; Takesue, Naohisa*

no journal, , 

X-ray PDF analysis of BiFeO-Bi(Mg,Ti)O mixture

Yoneda, Yasuhiro; Wada, Satoshi*

no journal, , 

BiFeO is a useful ferroelectric material, but it is not easy to reverse the polarization because the rhombohedral structure of the ferroelectric phase is greatly distorted, and attempts have been made to improve the dielectric properties by various additives. BaTiO and Bi(MgTi)O were selected as additives, and structural analysis was performed using synchrotron radiation. BiFeO has a rhombohedral structure and BaTiO has a tetragonal structure. Bi(MgTi)O has an antiferroelectric orthorhombic structure and is expected to behave as a buffer that binds BiFeO and BaTiO. The process of averaging the structure from micro to macro was clarified, and various changes were observed depending on the temperature. The flexibility of such a structure reduces the large distortion of BiFeO and enables polarization.

Local structure analysis of KNbO by high-energy X-ray diffraction

Yoneda, Yasuhiro; Ohara, Koji*; Nagata, Hajime*

no journal, , 

KNbO has been a candidate for the end member of a non-Pb ferroelectric materials. We performed local structure analysis of KNbO bulk ceramics by high-energy synchrotron X-ray measurements. It has recently established that temperature-driven structural phase transitions in several perovskite ferroelectric materials (PbTiO, BaTiO, and NaNbO) believed to be purely displacive, have a significant order-disorder component. We performed the local structure analysis in a wide-temperature range to observe order-disorder feature of KNbO. The lowest temperature structure of KNbO is rhombohedral, and we found that the local rhombohedral distortion maintained in the high-temperature cubic phase.