Epitaxial Strain Control of Relaxor Ferroelectric Phase Evolution. Issue 21 (10th April 2019)

• Record Type: Journal Article
• Authors: 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.
• Is Part Of: Advanced materials. Volume 31:Issue 21(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-10
• Subjects: diffuse scattering -- domain structure -- polar nanodomains -- relaxor ferroelectrics -- strain control; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201901060
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: 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 0.68PbMg1/3 Nb2/3 O3 –0.32PbTiO3 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. Abstract : Epitaxial strain‐induced evolution of polar structures and properties in a relaxor ferroelectric 0.68PbMg1/3 Nb2/3 O3 –0.32PbTiO3 reveals a surprisingly resilient relaxor behavior. Advances in thin‐film deposition and computational techniques are used to attain a comprehensive picture of strain‐induced phenomena in relaxor ferroelectrics.