K. Boldyreva, L. Pintilie, A. Lotnyk, I. B. Misirlioglu, N. D. Zakharov, M. Alexe, D. Hesse
Epitaxial antiferroelectric/ferroelectric PbZrO3/PbZr0.8Ti0.2O3 (PZO/PZT) superlattices were grown on SrRuO3-electroded SrTiO3(100) substrates by pulsed laser deposition. Polarization-field and switching current-voltage curves show a mixed antiferroelectric-ferroelectric behavior of the superlattices with an individual layer thickness above 10 nm, whereas below 10 nm the superlattices show only ferroelectric behavior. Clearly the PbZrO3 layers thinner than 10 nm experienced a transition into the ferroelectric state. X-ray diffraction reciprocal space mapping showed a corresponding orthorhombic-to-rhombohedral transition of the PbZrO3 layers.
Fig. 1: Cross section high-resolution TEM image of a coherently grown strained PZO/PZT superlattice with an individual layer thickness of 6 nm.
Fig. 2: Macroscopic polarization hysteresis curve of two superlattices with 100 nm overall thickness each. t – thickness of the individual layers. Blue: Loop with mixed antiferroelectric-ferroelectric character. Green: Loop with only ferroelectric character.
For details see Applied Physics Letters 91 (2007) 122915.