Induced ferroelectric phases in SrTiO3 by a nanocomposite approach

Inducing new phases in thick films via vertical lattice strain is one of the critical advantages of vertically aligned nanocomposites (VANs). In SrTiO3 (STO), the ground state is ferroelastic, and the ferroelectricity in STO is suppressed by the orthorhombic transition. Here, we explore whether vert...

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Bibliographic Details
Published in:Nanoscale 2020-09, Vol.12 (35), p.18193-18199
Main Authors: Enriquez, Erik, Li, Qian, Bowlan, Pamela, Lu, Ping, Zhang, Bruce, Li, Leigang, Wang, Haiyan, Taylor, Antoinette J, Yarotski, Dmitry, Prasankumar, Rohit P, Kalinin, Sergei V, Jia, Quanxi, Chen, Aiping
Format: Article
Language:English
Subjects:
Ferroelectric materials
Ferroelectricity
Lattice strain
Magnesium oxide
MATERIALS SCIENCE
Nanocomposites
Phases
Room temperature
Second harmonic generation
Strontium titanates
Thick films
Thin films
Vans
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Summary:Inducing new phases in thick films via vertical lattice strain is one of the critical advantages of vertically aligned nanocomposites (VANs). In SrTiO3 (STO), the ground state is ferroelastic, and the ferroelectricity in STO is suppressed by the orthorhombic transition. Here, we explore whether vertical lattice strain in three-dimensional VANs can be used to induce new ferroelectric phases in SrTiO3:MgO (STO:MgO) VAN thin films. The STO:MgO system incorporates ordered, vertically aligned MgO nanopillars into a STO film matrix. Strong lattice coupling between STO and MgO imposes a large lattice strain in the STO film. We have investigated ferroelectricity in the STO phase, existing up to room temperature, using piezoresponse force microscopy, phase field simulation and second harmonic generation. We also serendipitously discovered the formation of metastable TiO nanocores in MgO nanopillars embedded in the STO film matrix. Our results emphasize the design of new phases via vertical epitaxial strain in VAN thin films.
ISSN:2040-3364
2040-3372
DOI:10.1039/d0nr03460f