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Epitaxial Strain Control of Relaxor Ferroelectric Phase Evolution
Author(s) -
Kim Jieun,
Takenaka Hiroyuki,
Qi Yubo,
Damodaran Anoop R.,
Fernandez Abel,
Gao Ran,
McCarter Margaret R.,
Saremi Sahar,
Chung Linh,
Rappe Andrew M.,
Martin Lane W.
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201901060
Subject(s) - materials science , ferroelectricity , condensed matter physics , polar , scattering , dipole , chemical physics , relaxor ferroelectric , strain (injury) , polarization (electrochemistry) , epitaxy , molecular dynamics , nanotechnology , optics , dielectric , optoelectronics , physics , medicine , chemistry , layer (electronics) , quantum mechanics , astronomy
Understanding and ultimately controlling the large electromechanical effects in relaxor ferroelectrics requires intimate knowledge of how the local‐polar order evolves under applied stimuli. Here, the biaxial‐strain‐induced evolution of and correlations between polar structures and properties in epitaxial films of the prototypical relaxor ferroelectric 0.68PbMg 1/3 Nb 2/3 O 3 –0.32PbTiO 3 are investigated. X‐ray diffuse‐scattering studies reveal an evolution from a butterfly‐ to disc‐shaped pattern and an increase in the correlation‐length from ≈8 to ≈25 nm with increasing compressive strain. Molecular‐dynamics simulations reveal the origin of the changes in the diffuse‐scattering patterns and that strain induces polarization rotation and the merging of the polar order. As the magnitude of the strain is increased, relaxor behavior is gradually suppressed but is not fully quenched. Analysis of the dynamic evolution of dipole alignment in the simulations reveals that, while, for most unit‐cell chemistries and configurations, strain drives a tendency toward more ferroelectric‐like order, there are certain unit cells that become more disordered under strain, resulting in stronger competition between ordered and disordered regions and enhanced overall susceptibilities. Ultimately, this implies that deterministic creation of specific local chemical configurations could be an effective way to enhance relaxor performance.