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Uniaxial Strain-Controlled Ferroelastic Domain Evolution in BiFeO3

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journal contribution
posted on 20.03.2018, 00:00 by Abdullah Alsubaie, Pankaj Sharma, Jin Hong Lee, Jeong Yong Kim, Chan-Ho Yang, Jan Seidel
We investigate the effect of variable uniaxial tensile strain on the evolution of 71° ferroelastic domains in (001)-oriented epitaxial BiFeO3 (BFO) thin films using piezoresponse force microscopy (PFM). For this purpose, a newly designed bending stage has been employed, which allows tensile bending as wells as in situ PFM characterization. In situ PFM imaging reveals polarization–strain correlations at the nanoscale. Specifically, ferroelastic domains with in-plane polarization along the direction of applied tensile strain expand, whereas the adjoining domains with orthogonal in-plane polarization contract. The switching is mediated by significant domain wall roughening and opposite displacement of the successive walls. Further, the domains with long-range order are more susceptible to an applied external mechanical stimulus compared to the domains, which exhibit short-range periodicity. In addition, the imprint state of film reverses direction under applied tensile strain. Finally, the strain-induced changes in the domain structure and wall motion are fully reversible and revert to their as-grown state upon release of the applied stress. The strain-induced non-180° polarization rotation constitutes a route to control connected functionalities, such as magnetism, via coupled in-plane rotation of the magnetic plane in multiferroic BFO thin films.

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