Intrinsic ferroelectric properties of strained tetragonal PbZr0.2Ti0.8O3 obtained on layer-by-layer grown, defect-free single crystalline films

摘要

PbZrxTi1-xO3 (PZT) is one of the technologically most important ferroelectricmaterials. Bulk single-domain single crystals of PZT have never beensynthesized for a significant compositional range across the solid-solutionphase diagram. This leaves the fundamental properties of PZT under debate.Synthesis of defect-free single crystalline films enables us to unambiguouslydetermine the intrinsic quantities that describe ferroelectric materials, suchas spontaneous polarization and dielectric constant. Defect-free singlecrystalline, strained PbZr0.2Ti0.8O3 thin films were grown by pulsed-laserdeposition (PLD) onto vicinal SrTiO3 (001) single crystal substrates. Singlecrystalline SrRuO3 films fabricated by PLD were employed as bottom electrode.The PZT films have square shape hysteresis loops and remnant polarizationvalues of up to Pr= 110 micro C/cm2, which is considerably higher than thetheoretical value predicted for (unstrained) bulk single crystalline PZT of theinvestigated composition. The films have a dielectric constant eps33= 90 and apiezoelectric coefficient d33= 50 pm/V.