Enhanced ferroelectric properties of (1Â 1Â 1) oriented Pb(Hf0.3Ti0.7)O3 thin films deposited using self-buffered layer

Lead hafnate-titanate (PHT) thin films have been prepared via pulsed laser deposition (PLD) on Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by inserting a low temperature (200-400 °C) self-buffered layer. It is found that the self-buffered layers deposited at different temperatures have a great influence on the microstructure and electric properties. XRD spectra, including θ-2θ and ω scans, show that the PHT films with (1 1 1) preferred orientation were successfully deposited on substrates by inserting a low temperature self-buffered layer. Compared with the PHT films directly deposited at a high temperature, the PHT films with an inserted low temperature (300 °C) self-buffered layer have significantly enhanced electrical properties of four orders of magnitude lower leakage current density (3.2 × 10−8 A/cm2 at 150 kV/cm), 1.5 times larger remnant polarization (2Pr = 63 μC/cm2), 0.4 times smaller coercive field (2Ec = 190 kV/cm), and more excellent fatigue endurance (almost no degradation after 2 × 1010 switching cycles). The use of self-buffered layer is an effective approach to fabricate PHT ferroelectric materials with large ferroelectric polarization and long fatigue endurance.