Defect-Induced Hedgehog Polarization States in Multiferroics

Linze Li, Xiaoxing Cheng, Jacob R. Jokisaari, Peng Gao, Jason Britson, Carolina Adamo, Colin Heikes, Darrell G. Schlom, Long Qing Chen, Xiaoqing Pan

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Continuous developments in nanotechnology require new approaches to materials synthesis that can produce novel functional structures. Here, we show that nanoscale defects, such as nonstoichiometric nanoregions (NSNRs), can act as nano-building blocks for creating complex electrical polarization structures in the prototypical multiferroic BiFeO3. An array of charged NSNRs are produced in BiFeO3 thin films by tuning the substrate temperature during film growth. Atomic-scale scanning transmission electron microscopy imaging reveals exotic polarization rotation patterns around these NSNRs. These polarization patterns resemble hedgehog or vortex topologies and can cause local changes in lattice symmetries leading to mixed-phase structures resembling the morphotropic phase boundary with high piezoelectricity. Phase-field simulations indicate that the observed polarization configurations are mainly induced by charged states at the NSNRs. Engineering defects thus may provide a new route for developing ferroelectric- or multiferroic-based nanodevices.

Original languageEnglish (US)
Article number137602
JournalPhysical review letters
Volume120
Issue number13
DOIs
StatePublished - Mar 27 2018

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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