Search results for "Piezoresponse force microscopy"
showing 8 items of 8 documents
Two-phase dielectric polar structures in 0.1NBT-0.6ST-0.3PT solid solutions
2018
Abstract In this work we address the peculiarities of the macroscopic responses in ternary 0.1Na0·5Bi0·5TiO3-0.6SrTiO3-0.3PbTiO3 (0.1NBT-0.6ST-0.3PT) solid solutions. These solid solutions exhibit a spontaneous first order relaxor to normal ferroelectric phase transition. The phase transition is accompanied by a broad dielectric relaxation which expands over 10 orders of magnitude in frequency just above the phase transition temperature. The temperature dependence of polarization shows that non-zero net polarization persists above the phase transition temperature. Below the phase transition temperature, it is not possible to describe the temperature dependence of polarization with a power l…
Anisotropic carrier diffusion in single MAPbI(3) grains correlates to their twin domains
2020
Polycrystalline thin films and single crystals of hybrid perovskites – a material group successfully used for photovoltaic and optoelectronic applications – reportedly display heterogeneous charge carrier dynamics often attributed to grain boundaries or crystalline strain. Here, we locally resolved the carrier diffusion in large, isolated methylammonium lead iodide (MAPbI3) grains via spatial- and time-resolved photoluminescence microscopy. We found that the anisotropic carrier dynamics directly correlate with the arrangement of ferroelastic twin domains. Comparing diffusion constants parallel and perpendicular to the domains showed carriers diffuse around 50–60% faster along the parallel d…
Polar nanodomains and local ferroelectric phenomena in relaxor lead lanthanum zirconate titanate ceramics
2005
Transparent Pb0.9125La0.0975(Zr0.65Ti0.35)0.976O3 ceramics (conventionally abbreviated as PLZT 9.75/65/35) is a typical relaxor characterized by the absence of the ferroelectric order at the macroscopic scale. In this letter, we report on the observation of complex polar structures on the surface of this material via piezoresponse force microscopy (PFM). The irregular polarization patterns are associated with the formation of a glassy state, where random electric fields destroy the long-range ferroelectric order. The measure of the disorder, the correlation length of ∼50nm, was directly deduced from the PFM images. Local poling of relaxor ceramics resulted in the formation of a stable micro…
Ferroelectricity and piezoelectricity in soft biological tissue: Porcine aortic walls revisited
2017
Recently reported piezoresponse force microscopy (PFM) measurements have proposed that porcine aortic walls are ferroelectric. This finding may have great implications for understanding biophysical properties of cardiovascular diseases such as arteriosclerosis. However, the complex anatomical structure of the aortic wall with different extracellular matrices appears unlikely to be ferroelectric. The reason is that a prerequisite for ferroelectricity, which is the spontaneous switching of the polarization, is a polar crystal structure of the material. Although the PFM measurements were performed locally, the phase-voltage hysteresis loops could be reproduced at different positions on the tis…
Effect of surface disorder on the domain structure of PLZT ceramics
2017
ABSTRACTPb1-xLax(Zr0.65Ti0.35)1-x/4O3 (PLZT x/65/35) ceramics were studied by Piezoresponse Force Microscopy in order to understand the origin of domain structure as a function of La content. We show that the domain topology is mainly determined by the composition and grain size. The characteristic correlation length decreases with increasing La content, being sensitive also to the synthesis method. The behavior of the correlation length is linked to the macroscopic properties, showing a strong increase of disorder with La doping. The roughness exponent for the domain wall in PLZT 9/65/35 is close to 2/3 indicating 1D character of domain walls in relaxors.
Scanning probe microscopies applied to the study of the domain wall in a ferroelectric crystal.
2007
Summary Scanning near-field optical microscopy is capable of measuring the topography and optical signals at the same time. This fact makes this technique a valuable tool in the study of materials at nanometric scale and, in particular, of ferroelectric materials, as it permits the study of their domains structure without the need of chemical etching and, therefore, not damaging the surface (as will be demonstrated later). We have measured the scanning near-field optical microscopy transmission, as well as the topography, of an RbTiOPO4 single crystalline slab, which exhibits two different of macroscopic ferroelectric domains. A chemical selective etching has been performed to distinguish b…
Nanoscale Domain Structure in Relaxor PLZT x/65/35 Ceramics
2006
We present the experimental study of the geometry of the nanoscale domain structure in classical lead zirconate-titanate relaxor ceramics (Pb1 − x La x )(Zr0.65Ti0.35)O3 (PLZT) with La concentration from 5 to 10%. The analysis of the switching current data measured in rectangular pulses indicates the existence of random three-dimensional maze-type domain structure. High-resolution domain visualization performed using Piezoresponse Force Microscopy (PFM) reveals nanoscale domain patterns. The domain structures existing in PLZT ceramics after zero-field-cooling represent the nanoscale quasi-regular maze (“finger-print”). Statistical and fractal analysis of PFM images was performed for quantit…
Ferroelastic Fingerprints in Methylammonium Lead Iodide Perovskite
2016
Methylammonium lead iodide (MAPbI3) perovskite shows an outstanding performance in photovoltaic devices. However, certain material properties, especially the possible ferroic behavior, remain unclear. We observed distinct nanoscale periodic domains in the piezoresponse of MAPbI3(Cl) grains. The structure and the orientation of these striped domains indicate ferroelasticity as their origin. By correlating vertical and lateral piezoresponse force microscopy experiments performed at different sample orientations with X-ray diffraction, the preferred domain orientation is suggested to be the a1–a2-phase. The observation of these ferroelastic fingerprints appears to strongly depend on the film t…