Structural Study of Li1+x-yNb1-x-3yTix+4yO3 Solid Solutions

Published

June 1, 2002

Author(s)

L Farber, Igor Levin, A Borisevich, I E. Grey, Robert S. Roth, P K. Davies

Abstract

The structures of Lil+x-yNbl-,-3yTix+4yO3 solid solutions within the so-called M-phase field in the Li2O-Nb2O5-TiO2system were investigated using HRTEM and single crystal X-ray diffraction. The results demonstrated the phasefield is comprised of a homologous series of commensurate intergrowth structures with LiNbO3-type (LN) slabsseparated by single [Ti203 ]2+ layers with a corundum-type structure. The number of atomic layers in the LN slabdecreases with increasing Ti-content from - 55 to 3 in the metastable H-Li2Ti3O7 end-member. The LN slabsaccommodate a wide range of Ti4+/Nb5+ substitution, and for a given homologue the distribution of Ti and Nb isnot uniform across the slab. Single crystal studies of a structure composed of nine-layer LN slabs revealedpreferential segregation of Ti to the slab surfaces which apparently provides partial compensation for the charge othe adjacent [Ti203 ]2+ corundum layers. The excess cations in phases with x > 0 are accommodated through theformation of Li-rich Li2MO3-type layers in the middle of the LN slabs. The fraction of excess cation layersincreases with increasing Ti-content in the structure.

Citation

Journal of Solid State Chemistry

Volume

166

Issue

No. 1

Pub Type

Journals

Keywords

homologous series, intergrowth structures, Li₂O-Nb₂O₅-TiO₂ system, M-phase, microwave dielectrics

Citation

Farber, L. , Levin, I. , Borisevich, A. , Grey, I. , Roth, R. and Davies, P. (2002), Structural Study of Li_1+x-yNb_1-x-3yTi_x+4yO₃ Solid Solutions, Journal of Solid State Chemistry (Accessed July 1, 2024)