Large and Recoverable Electrostrain in Strained Ferroelectric Superlattices due to Domain Switching

doi:10.16356/j.1005-1120.2021.01.007

Transactions of Nanjing University of Aeronautics & Astronautics

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Archive > Volume 38 Issue 1 > 2021,38(1):75-83. DOI:10.16356/j.1005-1120.2021.01.007 Prev Next

Large and Recoverable Electrostrain in Strained Ferroelectric Superlattices due to Domain Switching

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Abstract:

The ferroelectric superlattices have been widely studied due to their distinguished electromechanical coupling properties. Under different biaxial mismatch strains， ferroelectric superlattices exhibit different domain structures and electromechanical coupling properties. A three-dimensional phase field model is employed to investigate the detailed domain evolution and electromechanical properties of the PbTiO3/SrTiO3（PTO/STO） superlattices with different biaxial mismatch strains. The phase field simulations show that the ferroelectric superlattice exhibits large electrostrain in the stacking direction when an external field is applied. Under a large compressive mismatch strain， vortex domains appear in ferroelectric layers with the thickness of 4 nm. The vortex domains become stable c-domain under a large external electric field， which remains when the electric field is removed. When the initial compressive mismatch strain decreases gradually， the waved or a1/a2 domains replaces the initial vortex domains in the absence of electric field. The fully polarized c-domain by a large electric field switches to diagonal direction domain or a/c domain when the electric field is small. Furthermore， when a biaxial tensile strain is applied to the superlattice， ferroelectric domains switch back to the initial a1/a2 twin-like domain structure， resulting in the recoverable and large electrostrain. This provides an effective way to obtain the large and recoverable electrostrain for the engineering application.

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This work was supported by the National Natural Science Foundation of China （Nos. 11672264， 11972320） and the Zhejiang Provincial Natural Science Foundation （No. LZ17A020001）.

Clc Number:

TB381