Orientation dependence of fatigue behavior in relaxor ferroelectric-PbTiO3 thin films

Pb[Yb1/2Nb1/2]O-3-PbTiO3 (PYbN-PT)/SrRuO3 (SRO) capacitors with Pt top electrodes were grown by pulsed laser deposition onto (100)(pc) LaAlO3 (LAO) and (111)(c) SrTiO3 (STO) substrates (the subscripts pc and c refer here to the pseudocubic and cubic perovskite cells, respectively). Suitable changes in both the substrate orientation and processing conditions allowed the growth of perovskite structured ferroelectric films with various degrees of orientation, from highly [001](pc)-oriented PYbN-PT/SRO/LAO to highly [111](pc)-oriented PYbN-PT/SRO/STO heterostructures. It was found that fatigue characteristics of such as-grown planar capacitors are strongly dependent on their crystalline orientation. In particular, [001](pc)-heteroepitaxial thin films result in fatigue-free capacitors up to 10(11) cycles, while [111](pc)-oriented heterostructures exhibit a marked degradation of the switchable polarization by ac voltage cycling. These data are consistent with recent findings of fatigue anisotropy in relaxor ferroelectric-PbTiO3 single crystals. (C) 2000 American Institute of Physics. [S0021-8979(00)05508-0].