Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Ordered Structure and Thermal Expansion in Tungsten Bronze Pb2K0.5Li0.5Nb5O15

Published

Author(s)

Kun Lin, Yangchun Rong, Hui Wu, Qingzhen Huang, Li You, Yang Ren, Longlong Fan, Jun Chen, Xianran Xing

Abstract

The crystal structure and thermal expansions of a new tetragonal tungsten bronze (TTB) ferroelectrics Pb2K0.5Li0.5Nb5O15 were systematically investigated by selected area electron diffraction (SAED), neutron powder diffraction, synchrotron XRD, and high temperature XRD. SAED and Rietveld refinement reveal that Pb2K0.5Li0.5Nb5O15 displays a commensurate superstructure of simple orthorhombic TTB structure at room temperature. The structure can be described with space group Bp21m. The transition to paraelectric phase (P4/mbm) occurs at 500 °C. Compared with Pb2KNb5O15 (PKN), the substitution of K+ with small Li+ into PKN causes the tilting of NbO6 octahedra away from c axis with Δ}θ approximately equal} 10 ° and raises the Curie temperature by 40 °C, and the negative thermal expansion coefficient (TEC) along polar b axis increases more than 50% in the temperature range 25 °C 500 °C. We present that, by introduction of Li+, the enhanced spontaneous polarization are responsible for the enhanced negative thermal expansion along b axis, which may be caused by more Pb^2+^ in the pentagonal caves.
Citation
Inorganic Chemistry
Volume
53

Keywords

Thermal expansion, tungsten bronze, ordering, crystal structure

Citation

Lin, K. , Rong, Y. , Wu, H. , Huang, Q. , You, L. , Ren, Y. , Fan, L. , Chen, J. and Xing, X. (2014), Ordered Structure and Thermal Expansion in Tungsten Bronze Pb<sub>2</sub>K<sub>0.5</sub>Li<sub>0.5</sub>Nb<sub>5</sub>O<sub>15</sub>, Inorganic Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=916678 (Accessed May 19, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created August 11, 2014, Updated October 12, 2021