Epitaxial Strain Control of Relaxor Ferroelectric Phase Evolution

• DOI: 10.1002/adma.201901060
• Publication Date: 2019-04-10T07:42:38Z
• Authors: Jieun Kim; Hiroyuki Takenaka; Yubo Qi; Anoop R. Damodaran; Abel Fernandez; Ran Gao; Margaret R. McCarter; Sahar Saremi; Linh Chung; Andrew M. Rappe; Lane W. Martin
• Keywords: Relaxor ferroelectric; Strain (injury)

Understanding and ultimately controlling the large electromechanical effects in relaxor ferroelectrics requires intimate knowledge of how local-polar order evolves under applied stimuli. Here, biaxial-strain-induced evolution correlations between polar structures properties epitaxial films prototypical ferroelectric 0.68PbMg1/3 Nb2/3 O3 -0.32PbTiO3 are investigated. X-ray diffuse-scattering studies reveal an from a butterfly- to disc-shaped pattern increase correlation-length ≈8 ≈25 nm with increasing compressive strain. Molecular-dynamics simulations origin changes patterns that strain induces polarization rotation merging order. As magnitude is increased, behavior gradually suppressed but not fully quenched. Analysis dynamic dipole alignment reveals that, while, for most unit-cell chemistries configurations, drives tendency toward more ferroelectric-like order, there certain unit cells become disordered strain, resulting stronger competition ordered regions enhanced overall susceptibilities. Ultimately, this implies deterministic creation specific local chemical configurations could be effective way enhance performance.