Berlin 2008 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Dielectric and ferroelectric thin films and nanostructures I

DF 11.2: Vortrag

Mittwoch, 27. Februar 2008, 14:20–14:40, EB 107

Ferroelectricity in antiferroelectric epitaxial PbZrO₃ films with different orientations — •Ksenia Boldyreva¹, Lucian Pintilie^1,2, Marin Alexe¹, and Dietrich Hesse¹ — ¹Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle/Saale, Germany — ²NIMP, P.O. Box MG-7, 077125 Bucharest-Magurele, Romania

PbZrO₃ (PZO) is a well known antiferroelectric (AFE) material with orthorhombic crystal structure. Due to antiparallel lead-ion shifts the remnant polarization is nominally zero. With a sufficiently large applied electric field, PZO undergoes a field-driven phase transition into a ferroelectric (FE), rhombohedral phase. However, the existence of a FE polarization along the c-axis of PZO (without applied field) was predicted by Jona et al. with an estimated value of 25 µ C/cm² [1]. We have investigated the temperature dependence of hysteresis and capacitance in PLD-grown epitaxial PZO films with two different orientations in the 4.2-400K temperature range. It was observed that (120)_o-oriented films (index o-orthorhombic) show a mixed AFE and FE behaviour on the entire temperature range, the FE behaviour being more stable at low temperatures. In contrast, the (001)_o-oriented films show a FE hysteresis only at temperatures up to 60 K. Above 60 K the hysteresis splits into two loops, typical for antiferroelectrics. The results indicate the coexistence of FE and AFE properties in PZO films, particularly at low temperature.
[1] F. Jona, G. Shirane, F. Mazzi, and R. Pepinsky, Phys. Rev. 105, 849 (1957)