Leveraging competition between energetically degenerate states to achieve large field-driven responses is a hallmark of functional materials, but routes to such competition are limited. Here, a new route to such effects involving domain-structure competition is demonstrated, which arises from strain-induced spontaneous partitioning of PbTiO3 thin films into nearly energetically degenerate, hierarchical domain architectures of coexisting c/a and a1/a2 domain structures. Using band-excitation piezoresponse force microscopy, this study manipulates and acoustically detects a facile interconversion of different ferroelastic variants via a two-step, three-state ferroelastic switching process (out-of-plane polarized c+ → in-plane polarized a → out-of-plane polarized c− state), which is concomitant with large nonvolatile electromechanical strains (≈1.25%) and tunability of the local piezoresponse and elastic modulus (>23%). It is further demonstrated that deterministic, nonvolatile writing/erasure of large-area patterns of this electromechanical response is possible, thus showing a new pathway to improved function and properties.
Bibliographical noteFunding Information:
A.R.D, S.P., and J.C.A. contributed equally to this work. A.R.D. and S.P. acknowledge support from the Army Research Office under grant W911NF-14-1-0104. A.R.D. acknowledges partial support from the Air Force Office of Scientific Research under grant FA9550-12-1-0471. J.C.A. acknowledges support from the U.S. Department of Energy, Office of Basic Energy Sciences (BES), Materials Project, under Grant No. EDCBEE for the development of novel functional materials. Y.C. and S.V.K. acknowledge support from U.S. Department of Energy, Office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division (MSED) under FWP Grant No. ERKCZ07. R.X. acknowledges support from the National Science Foundation under grant DMR-1451219. S.S. acknowledges support from the National Science Foundation under grant CMMI-1434147. J.K. acknowledges support from the National Science Foundation under grant OISE-1545907. L.R.D. acknowledges partial support from the Department of Energy, Office of Basic Energy Science under grant No. DE-SC0012375 and Intel Corp. T.A. and M.D.A. acknowledge support from a National Science Foundation Graduate Research Fellowship, grant DGE1106400. The scanning probe microscopy studies were conducted at the Center for Nanophase Materials Sciences which also provided support to R.K.V., Q.L., N.B., S.J., and S.V.K., and it is a DOE Office of Science User Facility. L.W.M. acknowledges support from the National Science Foundation under grant DMR-1708615.
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- electromechanical responses
- thin-film epitaxy
- three-state ferroelastic switching