Fig. 2: Intrinsic ferroelectricity for ~100 nm thick VAN SMO:BSO films at RT.
From: Nanoengineering room temperature ferroelectricity into orthorhombic SmMnO3 films
a Piezo-hysteresis response measured by PFM. Amplitude (circle and blue) and phase (square and red) of the PFM signal as a function of bias voltage. The inset AFM image shows the surface morphology of the film. b PFM phase contrast after −5 V writing (6 × 6 µm2), 5 V rewriting (4 × 4 µm2) and −5 V rewriting (2 × 2 µm2) at RT. The phase contrast remains after 24 h. c PUND measurements with 9 V (E = 500 kV cm−1), 1 ms pulse width and 1000 ms pulse delays for capturing both switching (*) and non-switching (^) polarisations. The net switching polarisation, 2PR, is ≈3.9 μC cm−2 and is consistent with PR obtained from P-E hysteresis. d Optical SHG signals at RT. Red and blue points represent p-wave and s-wave of the second harmonic electric field. The incidence angle is 45°. The solid line is a theoretical fit of the SHG data.
