Coexistence of ferroelectricity and antiferroelectricity in epitaxial $PbZrO3$ films with different orientations

The temperature dependence of the ferroelectric hysteresis and capacitance in $PbZrO3$ epitaxial films with $(120)O$ and $(001)O$ orientations was investigated in the $4.2–400K$ temperature range. It was found that the films with $(120)O$ orientation show a mixture of ferroelectric and antiferroelectric phases on the entire temperature range up to room temperature, with the ferroelectric phase more stable at low temperatures. Above room temperature the $(120)O$ oriented films seem to behave only as an antiferroelectric material. By contrast, films with $(001)O$ orientation show only ferroelectric behavior up to a temperature of about $60K$ when the single hysteresis loop splits into a double loop characteristic for antiferroelectrics. Above this temperature the $(001)O$ oriented films show only antiferroelectric behavior up to $400K$⁠. The temperature dependence of capacitance and loss tangent clearly shows a maximum at around $16K$ in the case of the $(001)O$ oriented film. This might be associated with a low temperature ferroelectric-antiferroelectric phase transition. However, this transition is not visible in the $(120)O$ oriented films.