Systematic Investigation of Ferroelectric Properties in x%YO1.5–(100–x%)Hf1–yZryO2 Films

The effect of composition on the ferroelectric properties was investigated using epitaxial x%YO1.5–(100–x%)Hf1–yZryO2 films. The tetragonal phase, with a composition near the phase boundaries with the orthorhombic or monoclinic phase, exhibits ferroelectricity through the field-induced phase transition from the tetragonal to the orthorhombic phase. Remarkably, the orthorhombic phase generated via the field-induced phase transition has a lower coercive field (Ec). The Ec could be controlled from 1400 (5%YO1.5–95%(Hf0.50Zr0.50)O2) to 2400 kV/cm (5%YO1.5–95%(Hf0.75Zr0.25)O2) with the same remnant polarization (Pr) value of ∼17 μC/cm2. These results are important for ferroelectric device applications with low-voltage drives.