Full text loading...
PFM measurement of rectangular ferroelectric domains written on PZT by applying to the scanning tip in an as-grown monodomain region [scale bar in (h) is ]. Each domain structure shows a 180° contrast in the vertical phase [(a) and (e)] with a corresponding minimal vertical amplitude at the domain wall [(b) and (f)] [white lines in (a) and (b) correspond to the profiles shown in (e) and (f)]. Two opposite nonzero signals (dark and bright colors) are observed in the lateral phase (c) perpendicularly to the AFM cantilever at the position of these domain walls, with a corresponding rise in the lateral amplitude (d). The orientation of the AFM cantilever is indicated in inset in (c). (g) Schematical representation of domain wall shear deformation due to locally nonzero coefficient (dashed red lines show the initial domain wall positions). (h) Topography of the region, showing a 4 Å rms surface roughness.
EFM measurements of rectangular ferroelectric domains written on PZT, immediately (a) and three months (b) after writing, with same vertical scale of 5° (horizontal scale bars are 1.4 and in (a) and (b), respectively). The upper and lower part of (a) correspond to and −1 V bias voltage applied to the tip during EFM, showing contrast inversion. (c) Time dependence of vertical and lateral PFM and EFM signals for domains written at , showing a decay of the EFM signal vs a stabilization of both PFM signals (dotted lines are a guide for the eye).
PFM images of an array of domains written on BFO with , 40 and 50 ms pulses on a prepolarized background: vertical (a), lateral [(b) and (c)] PFM phases, vertical (d), lateral [(e) and (f)] PFM amplitudes (horizontal bar is 100 nm). For the lateral measurements, the orientation of the cantilever is given in insets. The black contour in (a)–(f) corresponds to one of the written out-of-plane domain walls in (a). (g) Orientation of the crystalline axis of the substrate and the BFO film and of the in-plane projection of the eight possible orientations of the polarization. and – stand for the out-of-plane component of the polarization going out or in the paper respectively.
Article metrics loading...