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Understanding the dynamic behavior of interfaces in ferroic materials is an important field of research with widespread practical implications, as the motion of domain walls and phase boundaries are associated with substantial increases in dielectric and piezoelectric effects. Although commonly studied in the macroscopic regime, the local dynamics of interfaces have received less attention, with most studies limited to domain growth and/or reversal by piezoresponse force microscopy (PFM). Here, spatial mapping of local domain wall‐related relaxation in a tensile‐strained PbTiO3 thin film using time‐resolved band‐excitation PFM is demonstrated, which allows exploring of the field‐induced strain (piezoresponse) as a function of applied voltage and time. Through multivariate statistical analysis on the resultant 4‐dimensional dataset (x,y,V,t) with functional fitting, it is determined that the relaxation is strongly correleated with the distance to the domain walls, and varies based on the type of domain wall present in the probed volume. Phase‐field modeling shows the relaxation behavior near and away from the interfaces, and confirms the modulation of the z‐component of polarization by wall motion, yielding the observed piezoresponse relaxation. These studies shed light on the local dynamics of interfaces in ferroelectric thin films, and are therefore important for the design of ferroelectric‐based components in microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Giant electromechanical response viaferroelastic domain switching is achieved in epitaxial (001) ferroelectric tetragonal (T) PbZr0.3Ti0.7O3/rhombohedral (R) PbZr0.55Ti0.45O3 bilayers, grown on La0.67Sr0.33MnO3 buffered SrTiO3 substrates. X-ray diffraction and transmission electron microscopy show that the domain structure of the T films is tuned as a function of its thickness, from a fully a1/a2-domains (30 nm thick T layer) to a three domain stress-free c/a1/c/a2 polytwin state (100 nm thick T layer). A large switchable polarization is found up to 65 μC cm−2. Quantitative piezoelectric force microscopy reveals enhanced piezoelectric coefficients, with d33 coefficients ranging from 250 to 350 pm V−1, which is up to seven times higher than the nominal PbZrxTi1−xO3 thin film values. These are attributed to the motion of nanoscale ferroelastic domains. Fatigue testing proves that these domains are reversible and repeatable up to 107 cycles. In-situ X-ray synchrotron measurements reveal that the ferroelastic domain switching is promoted by a pulsating strain effect imposed by the R layer. The study reports a fundamental understanding of the origin of giant piezoelectric coefficients in epitaxial ferroelectric bilayers. [ABSTRACT FROM AUTHOR]

The nonlinear response of a ferroic to an applied field has been studied through the phenomenological Rayleigh Law for over a hundred years. Yet, despite this, the fundamental physical mechanisms at the nanoscale that lead to macroscopic Rayleigh behavior have remained largely elusive, and experimental evidence at small length scales is limited. Here, it is shown using a combination of scanning probe techniques and phase field modeling, that nanoscale piezoelectric response in prototypical Pb(Zr,Ti)O3 films appears to follow a distinctly non-Rayleigh regime. Through statistical analysis, it is found that an averaging of local responses can lead directly to Rayleigh-like behavior of the strain on a macroscale. Phase-field modeling confirms the twist of the ferroelastic interface is key in enhancing piezoelectric response. The studies shed light on the nanoscale origins of nonlinear behavior in disordered ferroics. [ABSTRACT FROM AUTHOR]