Fig. 2

The ferroelectricity and vortex ferroelectric domains of h-Lu_0.6Sc_0.4FeO₃. Room-temperature PFM images of cleaved surfaces of crystals after a 100 °C/h, b 10 °C/h, and c 1 °C/h cooling in the 1400–1200 °C temperature range. (d) The large-range PFM image of the area A of LSFO1 (the black dashed square corresponds to (c)). (e) The density of defects as a function of cooling rates. Error bars of the defect density for 1 °C/h, 10 °C/h, and 100 °C/h cooling are ±0.005 μm⁻², ±0.16 μm⁻², and ±0.4 μm⁻² respectively. Data of ErMnO₃ and TmMnO₃ is obtained from ref. 25. (f) PFM image of another area in LSFO1 (area B). (g) Room-temperature P-E loops of LSMO2 at 2702 Hz, which prove its robust and switchable ferroelectricity. Scale bars are 2 μm in a, b and c, 5 μm in d and f