Faculty Profiles - TODA Kenji

Papers - TODA Kenji

Division display 221 - 225 of about 225 ／ All the affair displays >>

Crystal structure determination of ion-exchangeable layered perovskite compounds, K2La2Ti3O10 and Li2La2Ti3O10 Reviewed

Kenji Toda, Jun Watanabe, Mineo Sato

Materials Research Bulletin 31 ( 11 ) 1427 - 1435 1996

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Ltd

The crystal structure of the ion-exchangeable layered perovskite compounds K2La2Ti3O10 and Li2La2Ti3O10 were determined by Rietveld analysis for the powder X-ray diffraction pattern. Although the framework of the perovskite layer of lithium compound is the same as those of the corresponding sodium and potassium compounds, a fundamental difference exists. The lithium ions within the interlayer have a tetrahedral coordination because the ionic radius is too small for a rock-salt coordination. The layered perovskite compound Li2La2Ti3O10 exhibits a new phase analogous to the Ruddlesden-Popper phase.

DOI： 10.1016/0025-5408(96)00135-3

Scopus

researchmap

Synthesis and ionic conductivity of novel layered perovskite compounds, AgLaTiO4 and AgEuTiO4 Reviewed

Kenji Toda, Satoru Kurita, Mineo Sato

Solid State Ionics 81 ( 3-4 ) 267 - 271 1995.11

Language：English Publishing type：Research paper (scientific journal)

Novel compounds, AgLaTiO4 and AgEuTiO4, have been synthesized by an ion-exchange reaction from parent compounds, NaLaTiO4 and NaEuTiO4. The crystal structure of the silver ion-exchanged compounds was determined by the Rietveld analysis for powder XRD patterns. The silver ion-exchange compounds retain the structural characteristics of the parent phases. The interlayer silver ions in the silver ion-exchanged compounds have a rock-salt type coordination. These compounds, which are probably metastable, could only be obtained by the ion-exchange reaction. The ionic conductivities attributed to the interlayer silver ions were observed at high temperatures. The ionic conductivity of AgLaTiO4 was much higher than that of NaLaTiO4. Such a high ionic conductivity is probably due to the higher polarizability of silver ion. © 1995.

DOI： 10.1016/0167-2738(95)00184-8

Scopus

researchmap

Luminescence properties of layered perovskites activated by Eu3+ ions Reviewed

Kenji Toda, Yutaka Kameo, Masatoshi Ohta, Mineo Sato

Journal of Alloys and Compounds 218 ( 2 ) 228 - 232 1995.3

Language：English Publishing type：Research paper (scientific journal)

Dependence of emission intensity on Eu3+ concentration in Na2Gd2(1-x)Eu2xTi3O10 with a triple perovskite layer and NaGd1-xEuxTiO4 with a single perovskite layer was studied. Critical values for concentration quenching are x = 0.40 for Na2Gd2(1-x)Eu2xTi3O10 and x = 0.25 for NaGd1-xEuxTiO4. The difference in the critical concentration between both compounds is discussed in terms of their crystal structures determined by the powder X-ray diffraction patterns using the Rietveld method. The concentration quenching found in these compounds can be explained by means of a percolation model with nearly two-dimensional interactions between Eu3+ sites in the host lattice. © 1995.

DOI： 10.1016/0925-8388(94)01395-0

Scopus

researchmap

Crystal structure and ionic conductivity of a layered perovskite, Na2La2Ti3O10 Reviewed

Kenji Toda, Yutaka Kameo, Masayuki Fujimoto, Mineo Sato

Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan 102 737 - 741 1994

Language：English Publishing type：Research paper (scientific journal) Publisher：Ceramic Soc of Japan

An ion-exchangeable layered perovskite compound, Na2La2Ti3O10, was directly synthesized by a solid-state reaction. The crystal structure of Na2La2Ti3O10 was determined by electron diffraction analysis and Rietveld analysis for the powder X-ray diffraction pattern. The unit cell is tetragonal with a = 0.383528(7) nm, c = 2.85737(7) nm and Z = 2 with the space group I4/mmm (No. 139). The structure of this compound is analogous to that of the Ruddlesden-Popper phases. The ionic conductivity of Na2La2Ti3O10 was not very high compared with those of niobate compounds, NaLaNb2O7 and NaCa2NaNb4O13. Such a low ionic conductivity is due to the rigid rock-salt-type coordination around sodium ions located at the interlayer.

DOI： 10.2109/jcersj.102.737

Scopus

researchmap

層状ペロブスカイトK2La2Ti3O10およびその銀イオン交換体の構造とイオン伝導性 Reviewed

佐藤峰夫, 戸田健司, 渡辺潤, 上松和義

日本化学会誌 5 640 - 646 1993.12

　 PREV - NEXT 　

<TODA Kenji>

Papers - TODA Kenji