The polarization-electric-field hysteresis curves of the polar c-axis-grown orthorhombic GaFeO3 (o-GFO) film on a SrRuO3/STO substrate show the net switching polarization of ~35 μC cm−2 with an unusually high coercive field (Ec) of ±1400 kV cm−1 at room temperature. The positive-up and negative-down measurement also demonstrates the switching polarization of ~26 μC cm−2. The activation energy for the polarization switching, as obtained by density-functional theory calculations, is remarkably high, 1.05 eV per formula unit. We have theoretically shown that this high value accounts for the extraordinary high Ec and the stability of the polar Pna21 phase over a wide range of temperature up to 1368 K.
- Seungwoo Song
- Hyun Myung Jang
- James F Scott
