Three‐State Ferroelastic Switching and Large Electromechanical Responses in PbTiO3 Thin Films

• DOI: 10.1002/adma.201702069
• Publication Date: 2017-07-31T07:22:54Z
• Authors: Anoop R. Damodaran; Shishir Pandya; Josh C. Agar; Ye Cao; Rama K. Vasudevan; Ruijuan Xu; Sahar Saremi; Qian Li; Jieun Kim; Margaret R. McCarter; Liv R. Dedon; Tom Angsten; Nina Balke; Stephen Jesse; Mark Asta; Sergei V. Kalinin; Lane W. Martin
• Keywords: Piezoresponse force microscopy; Ferroelasticity

Leveraging competition between energetically degenerate states to achieve large field-driven responses is a hallmark of functional materials, but routes such are limited. Here, new route effects involving domain-structure demonstrated, which arises from strain-induced spontaneous partitioning PbTiO3 thin films into nearly degenerate, hierarchical domain architectures coexisting c/a and a1 /a2 structures. Using band-excitation piezoresponse force microscopy, this study manipulates acoustically detects facile interconversion different ferroelastic variants via two-step, three-state switching process (out-of-plane polarized c+ → in-plane out-of-plane c- state), concomitant with nonvolatile electromechanical strains (≈1.25%) tunability the local elastic modulus (>23%). It further demonstrated that deterministic, writing/erasure large-area patterns response possible, thus showing pathway improved function properties.