skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on April 27, 2019

Title: Giant thermally-enhanced electrostriction and polar surface phase in L a 2 M o 2 O 9 oxygen ion conductors

Ferroelectrics possess spontaneous electric polarization at macroscopic scales which nonetheless imposes strict limitations on the material classes. Recent discoveries of untraditional symmetry-breaking phenomena in reduced material dimensions have indicated feasibilities to extend polar properties to broader types of materials, potentially opening up the freedom for designing materials with hybrid functionalities. Here in this paper, we report the unusual electromechanical properties of La 2Mo 2O 9 (LAMOX) oxygen ion conductors, systematically investigated at both bulk and surface length levels. We first observed giant electrostriction effects in La 2Mo 2O 9 bulk ceramics that are thermally enhanced in concert with their low-energy oxygen-vacancy hopping dynamics. Moreover, while no clear bulk polarization was detected, the surface phases of LAMOX were found to be manifestly polar, likely originating from the coupling between the intrinsic structural flexibilities with strain gradients (i.e., flexoelectricity) and/or chemical heterogeneities present in the materials. These findings identify La 2Mo 2O 9 as a promising electromechanical material system and suggest that the flexible structural and chemical configurations in ionically active materials could enable fundamentally different venues to accommodate electric polarization.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [5] ;  [3] ;  [5] ;  [6] ;  [4] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  2. Australian National Univ., Canberra, ACT (Australia). Research School of Chemistry
  3. Univ. of Cambridge (United Kingdom). Dept. of Earth Sciences
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  5. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  6. Univ. of Washington, Seattle, WA (United States). Dept. of Mechanical Engineering
Publication Date:
Grant/Contract Number:
AC02-06CH11357; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 2; Journal Issue: 4; Journal ID: ISSN 2475-9953
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1465143
Alternate Identifier(s):
OSTI ID: 1434987