Fig. 3
From: Electrically reversible cracks in an intermetallic film controlled by an electric field
Reversible crack driven by an electric field. Atomic force microscopy images (5 × 5 μm2) of a single crack in the MnPt film after scanning the gate electric field E G a from +3.3 kV/cm to 0 kV/cm and b from −3.3 kV/cm to 0 kV/cm. c, d Schematics showing that electric-field (E)-induced reversible and nonvolatile crack formation and closure on the (001) PMN-PT surface can result from a reversible and nonvolatile E-induced 109° polarization switching. A two-domain configuration consisting of one switchable polarization domain and one pinned domain is considered. Such reversible 109° polarization switching can repeatedly induce an in-plane shear strain of about 0.2% in the switchable domain, which will repeatedly stress the domain boundary. The 0.2% strain is calculated based on the lattice parameters (a,θ) of the rhombohedral (001) PMN-PT. e Phase-field simulations of the crack evolution when the strain is ON (the first image in the first row) and OFF (the remaining images). Color bar shows the magnitude of the phase variable, which equals 1 in the crack region and 0 in the PMN-PT, and changes continuously across their interface
