Study of the long time relaxation of the weak ferroelectricity in PbZrO3 antiferroelectric thin film using Positive Up Negative Down and First Order Reversal Curves measurements

The weak ferroelectric contribution to the polarization of antiferroelectric lead zirconate (PZO) thin films has been investigated using PUND (Positive Up Negative Down) pulse measurements and hysterons decomposition by First Order Reversal Curves (FORC) technique. The PUND allows decomposing the measured current, obtained from the polarization-electric field loop measurements, into a switching and a non-switching contribution. We show that the weak ferroelectric phase is enhanced when a large electric field has been previously applied to the material, in order to switch from the antiferroelectric to the ferroelectric phase. Using the PUND measurement at fields below the antiferroelectric to ferroelectric phase transition, the polarization loop corresponding only to the ferroelectric switching contribution has been determined revealing that this contribution to the overall polarization is small. FORC measurements, however, indicate that the ferroelectric phase is present at different fields. At low fields, a quite homogeneous distribution of hysterons exists and at large field, a high concentration of hysterons at a field near to the antiferroelectric to ferroelectric phase transition can be seen. Moreover, when changing the delay between pulses of the PUND and the FORC measurements, we show that this weak ferroelectricity contribution is metastable and decreases with time.

Automated summary

The weak ferroelectric contribution to the polarization of antiferroelectric lead zirconate (PZO) thin films was investigated using PUND pulse measurements and FORC technique. The PUND allowed decomposing the measured current into a switching and a non-switching contribution. The weak ferroelectric phase was enhanced when a large electric field was previously applied to switch from the antiferroelectric to the ferroelectric phase. The FORC measurements showed a presence of ferroelectric phase at different fields, with a high concentration near the antiferroelectric to ferroelectric phase transition, and the weak ferroelectricity contribution was found to be metastable and decreasing with time when changing the delay between PUND and FORC measurements.