Figure 1: Bipolar BEPS switching loops of 50 nm BFO/STO.
From: Giant elastic tunability in strained BiFeO3 near an electrically induced phase transition
(a) Reciprocal space map near the STO 332 reflection showing three-fold splitting indicative of a MA structure of BFO. Scale bar, 1/3.905 Å−1. (b,c) Morphology (b) and corresponding lateral PFM (c) images; Inset in c shows the corresponding vertical PFM image after the center square area was poled with 10 V tip bias. The cantilever alignment adopted in all BEPS measurements is shown in b. Scale bar, 1 μm. (d–h) Single-point BEPS performed under ascending bias windows as shown in d, which also illustrates the measured piezoresponse amplitude spectrographs; total time length=2.3 s. e is a schematic representation for the chirp-type BE waveform and on/off-field d.c. switching sequences. f–h are the fitted frequency (f), piezoresponse (g) and Q factor (h) loops with their sense marked by arrows and colour coded by the bias windows shown in d. (i) Histogram of the on-field piezoresponse loops acquired from 50 × 50 points over a 1 × 1 μm2 region. (j,k) Single-point in-plane BEPS frequency (j) and piezoresponse (k) loops acquired in the lateral mode with the sense marked by arrows. a.u., arbitrary unit.
