Phase transitions and octahedral rotations in epitaxial Ag(Ta_xNb_1-x)O₃ thin films under tensile strain

Journal Article · Fri Feb 27 00:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4913283· OSTI ID:1356997

Johnson-Wilke, R. L. ^[1]; Wilke, R. H. T. ^[1]; Yeager, C. B. ^[1]; Tinberg, D. S. ^[1]; Reaney, I. M. ^[2]; Levin, I. ^[3]; Fong, D. D. ^[4]; Trolier-McKinstry, S. ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States). Materials Research Inst. Materials Science and Engineering Dept.
2. Univ. of Sheffield (United Kingdom). Dept. of Engineering Materials
3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Materials Measurement Science Division
4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division

In this paper, epitaxial Ag(Ta_0.5Nb_0.5)O₃ (ATN) films under tensile strain were deposited on (Ba_0.4Sr_0.6)TiO₃/LaAlO₃ (001)_p and KTaO₃ (001) substrates. These films exhibited a domain structure with the c-axis aligned primarily along the in-plane direction in contrast with the poly-domain nature of bulk ATN ceramics or relaxed films. While the generic phase transition sequence of the tensile films was qualitatively similar to bulk, the tetragonal and orthorhombic phase field regions expanded by ~270 °C in ATN/(Ba_0.4Sr_0.6)TiO₃/LaAlO₃. Furthermore, the films were found to be in the M₃ (complex octahedral tilting with disordered Nb/Ta displacements) phase at room temperature with either significantly reduced tilt angles or a suppression of the long range order of the complex tilt as compared to bulk materials. It was observed that the octahedral tilt domains were oriented with the complex tilt axes lying in the plane of the film due to the tensile strain. Finally, this work demonstrates that tensile strain can be used to strain-engineer materials with complex tilt systems and thereby modify functional properties.

• Research Organization: Pennsylvania State Univ., University Park, PA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
• Contributing Organization: Univ. of Sheffield (United Kingdom); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
• Grant/Contract Number: AC02-06CH11357; DMR-0602770; DMR-0820404; DMR-0908718
• OSTI ID: 1356997
• Alternate ID(s): OSTI ID: 1228557
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 8; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Thin film structure
Niobium
Superlattices
Materials properties
Phase transitions