Thickness‐dependent domain wall reorientation in 70/30 lead magnesium niobate‐ lead titanate thin films

Abstract

Continued reduction in length scales associated with many ferroelectric film‐based technologies is contingent on retaining the functional properties as the film thickness is reduced. Epitaxial and polycrystalline lead magnesium niobate‐lead titanate (70PMN‐30PT) thin films were studied over the thickness range of 100‐350 nm for the relative contributions to property thickness dependence from interfacial and grain‐boundary low permittivity layers. Epitaxial PMN‐PT films were grown on SrRuO3/(001)SrTiO3, while polycrystalline films with {001}‐Lotgering factors >0.96 were grown on Pt/TiO2/SiO2/Si substrates via chemical solution deposition. Both film types exhibited similar relative permittivities of ~300 at high fields at all measured thicknesses with highly crystalline electrode/dielectric interfaces. These results, with the DC‐biased and temperature‐dependent dielectric characterization, suggest irreversible domain wall mobility is the major contributor to the overall dielectric response and its thickness dependence. In epitaxial films, the irreversible Rayleigh coefficients reduced 85% upon decreasing thickness from 350 to 100 nm. The temperature at which a peak in the relative permittivity is observed was the only measured small signal quantity which was more thickness‐dependent in polycrystalline than epitaxial films. This is attributed to the relaxor nature present in the films, potentially stabilized by defect concentrations, and/or chemical inhomogeneity. Finally, the effective interfacial layers are found to contribute to the measured thickness dependence in the longitudinal piezoelectric coefficient.

Energy Storage Performance and Electric Breakdown Field of Thin Relaxor Ferroelectric PLZT Films Using Microstructure and Growth Orientation Control

“…The dielectric constant increases with film thickness. Such behavior was reported previously and attributed to the change of the relative thickness fraction of a dead-layer (at the film/electrode layer) , and/or the enhancement of 180°-domain wall motion (extrinsic contribution) with increasing film thickness. , …”

“…Such behavior was reported previously and attributed to the change of the thickness fraction of a dead-layer (at the film/electrode layer) 19,20 and/ or the enhancement of 180°-domain wall motion (extrinsic contribution) with increasing film thickness. 21,22 In order to determine the electric breakdown field, the P−E loops were measured from a low maximum electric field (such as 200 kV cm −1 ) up to the electric field where the capacitors failed. Parts a and b of Figure 5 show the P−E loops of typical 1000 nm-thick PLZT thin films grown on CNOns/Si and TiOns/Si substrates, measured up to their E BD values.…”

Synthesis, Giant Dielectric, and Pyroelectric Response of [001]-Oriented Pr3+ Doped Pb(Mg1/3Nb2/3)O3-PbTiO3 Ferroelectric Nano-Films Grown on Si Substrates

“…It was found that 2.5% Pr-PMN-PT thin films were mostly in the perovskite phase with a little pyrochlore phase when annealed for 1 min, which was further crystallized to a single perovskite phase structure after one more minute annealing. However, a peak of the pyrochlore phase was found again in the sample annealed for 5 min, which can be ascribed to the greater lead loss caused by the longer time annealing [19].…”

“…The values of ε r , p y , and p r in 2.5% Pr-PMN-PT thin films were on the order of 2400, 167 μC/m 2 K, and 17.3 μC/cm 2 , showing 110%, 123%, and 50% higher factors respectively than those in pure PMN-PT thin films. Compared with PMN-0.30PT grown by a chemical solution deposition (CSD) method [19], the ε r in PMN-0.30PT thin films on Si substrate was lower than that of the sample synthesized on perovskite structure single crystal substrates. A similar tendency of pyroelectric property was found in PMN-0.30PT thin film grown on various substrates.…”

“…For PMN-based bulk crystals, the pure perovskite structure can easily be synthesized using the two-step columbite precursor method [15,16,17]. On the contrary, the second pyrochlore phase in PMN-PT thin films is related to many factors, for example annealing temperature/time [18], sample thickness [19], excess Pb content [20,21], etc., which restrict the pyroelectric, piezoelectric, and dielectric properties in PMN-PT thin films.…”