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Title: Tuning piezoelectric properties through epitaxy of La 2Ti 2O 7 and related thin films

Current piezoelectric sensors and actuators are limited to operating temperatures less than ~200ºC due to the low Curie temperature of the piezoelectric material. The strengthening the piezoelectric coupling of high-temperature piezoelectric materials, such as La 2Ti 2O 7 (LTO), would allow sensors to operate across a broad temperature range. The crystalline orientation and piezoelectric coupling direction of LTO thin films can be controlled by epitaxial matching to SrTiO 3(001), SrTiO 3(110), and rutile TiO 2(110) substrates via pulsed laser deposition. The structure and phase purity of the films are investigated by x-ray diffraction and scanning transmission electron microscopy. Piezoresponse force microscopy is used to measure the in-plane and out-of-plane piezoelectric coupling in the films. The strength of the out-of-plane piezoelectric coupling can be increased when the piezoelectric direction is rotated partially out-of-plane via epitaxy. The strongest out-of-plane coupling is observed for LTO/STO(001). Deposition on TiO 2(110) results in epitaxial La 2/3TiO 3, an orthorhombic perovskite of interest as a microwave dielectric material and an ion conductor. La 2/3TiO 3 can be difficult to stabilize in bulk form, and epitaxial stabilization on TiO 2(110) is a promising route to realize La 2/3TiO 3 for both fundamental studies and device applications. Overall,more » these results confirm that control of the crystalline orientation of epitaxial LTO-based materials can govern the resulting functional properties.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [3] ;  [3] ;  [3] ; ORCiD logo [1] ;  [4] ;  [5] ; ORCiD logo [6]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of). Dept. of Materials Science and Engineering
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical and Computational Sciences Directorate; Auburn Univ., AL (United States). Dept. of Physics
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). National Security Directorate
  6. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environment Directorate
Publication Date:
Report Number(s):
PNNL-SA-128769
Journal ID: ISSN 2045-2322; 143396
Grant/Contract Number:
AC02-06CH11357; AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1461294