Engineering Ferroelectric Phases in BaTiO3 Films via Buffer-Layer Induced Misfit Strain Reversal
Abstract
Controlling ferroelectric phase symmetry through strain engineering is crucial for tailoring polarization topology and functional properties in oxide-based devices. Here, we show that a thin conductive buffer layer can override substrate-induced strain in BaTiO3 (BTO) films on MgO. Although the lattice parameter of MgO(001) would be expected to induce tensile misfit strain, in 500~nm BaTiO3 films the thermal-expansion mismatch dominates, resulting in effective compressive stress upon cooling. Inserting a 50-nm La0.67Sr0.33MnO3 (LSMO) buffer layer reverses the effective strain state from compressive to tensile. Using temperature-dependent polarized Raman spectroscopy, X-ray diffraction, and piezoresponse force microscopy, we reveal an unconventional phase sequence upon cooling: paraelectric → orthorhombic (aa-phase, ∼407 K) → monoclinic (r-phase, ∼300-345 K), characterized in-plane and tilted polarization components. The LSMO layer not only serves as a bottom electrode but also modifies the strain state, while interfacial charge redistribution induces a built-in electric field, evidenced by self-polarization and asymmetric PFM hysteresis. These findings highlight the critical role of conductive buffer layers in controlling ferroelectric symmetry and enabling oxide heterostructures with tailored polarization textures for low-power spintronics, tunable microwave devices, and neuromorphic computing.
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BibTeX
@misc{mikheykin2026engineering,
title = {{Engineering Ferroelectric Phases in BaTiO$_3$ Films via Buffer-Layer Induced Misfit Strain Reversal}},
author = {A. S. Mikheykin and N. V. Lyanguzov and A. S. Konstantinov and V. B. Shirokov and E. D. Linnik and T. Bondar and A. G. Razumnaya},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16766},
eprint = {2610.16766},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16766},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Engineering Ferroelectric Phases in BaTiO_3 Films via Buffer-Layer Induced Misfit Strain Reversal
AU - A. S. Mikheykin
AU - N. V. Lyanguzov
AU - A. S. Konstantinov
AU - V. B. Shirokov
AU - E. D. Linnik
AU - T. Bondar
AU - A. G. Razumnaya
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.16766
UR - https://arxiv.org/abs/2610.16766
AB - Controlling ferroelectric phase symmetry through strain engineering is crucial for tailoring polarization topology and functional properties in oxide-based devices. Here, we show that a thin conductive buffer layer can override substrate-induced strain in BaTiO_3 (BTO) films on MgO. Although the lattice parameter of MgO(001) would be expected to induce tensile misfit strain, in 500~nm BaTiO_3 films the thermal-expansion mismatch dominates, resulting in effective compressive stress upon cooling. Inserting a 50-nm La_0.67Sr_0.33MnO_3 (LSMO) buffer layer reverses the effective strain state from compressive to tensile. Using temperature-dependent polarized Raman spectroscopy, X-ray diffraction, and piezoresponse force microscopy, we reveal an unconventional phase sequence upon cooling: paraelectric → orthorhombic (aa-phase, ∼407 K) → monoclinic (r-phase, ∼300-345 K), characterized in-plane and tilted polarization components. The LSMO layer not only serves as a bottom electrode but also modifies the strain state, while interfacial charge redistribution induces a built-in electric field, evidenced by self-polarization and asymmetric PFM hysteresis. These findings highlight the critical role of conductive buffer layers in controlling ferroelectric symmetry and enabling oxide heterostructures with tailored polarization textures for low-power spintronics, tunable microwave devices, and neuromorphic computing.
ER -