Ferroelectric domain wall dynamics characterized with X-ray photon correlation spectroscopy

Abstract

Technologically important properties of ferroic materials are determined by their intricate response to external stimuli. This response is driven by distortions of the crystal structure and/or by domain wall motion. Experimental separation of these two mechanisms is a challenging problem which has not been solved so far. Here, we apply X-ray photon correlation spectroscopy (XPCS) to extract the contribution of domain wall dynamics to the overall response. Furthermore, we show how to distinguish the dynamics related to the passing of domain walls through the periodic (Peierls) potential of the crystal lattice and through the random potential caused by lattice defects (pinning centers). The approach involves the statistical analysis of correlations between X-ray speckle patterns produced by the interference of coherent synchrotron X-rays scattered from different nanosize volumes of the crystal and identification of Poisson-type contribution to the statistics. We find such a contribution in the thermally driven response of the monoclinic phase of a ferroelectric PbZrTiO crystal and calculate the number of domain wall jumps in the studied microvolume.

X-Ray Photon Correlation Spectroscopy with Coherent Nanobeams: A Numerical Study

“…Heterogeneous systems with nanoscale heterogeneities being ubiquitous, the number of studies that could benefit from nXPCS is immense: liquids, glasses, self-organised systems, oscillatory chemical reactions, magnetic spin ices, polymers or colloids in confinement, nanofluidics. To mention only two types: (a) Similar studies to the one reported by Zhang et al [50] on the spatially heterogeneous dynamics in metallic glass forming systems can be envisaged, not with the spectacularly high spatial resolution reported in that work, which has been obtained using electrons as probe, but on more complex systems or environments that are not accessible with electron probes; (b) Using a sufficiently small beam, it will be possible to probe the inter-island (or collective) and intra-island magnetic reversal dynamics in artificial spin ice structures or magnetic domains [28][29][30]51]. Morley et al have studied square arrays of 30 × 70 nm size magnetic islands, using a 10 µm diameter beam, at 9.6 • incidence angle [30].…”

Towards molecular movies with X-ray photon correlation spectroscopy

“…4, bottom) and help to identify and quantify aging phenomena, phase transitions or sudden rearrangement events such as avalanches. 53,[77][78][79] A prominent example in this context is the degree of temporal heterogeneity w 4 (t) expressed by the fluctuations…”

Stress breaks universal aging behavior in a metallic glass

“…Via the analysis of an intensity autocorrelation function, the structural relaxation time τ is obtained at any time. This approach has enabled deep insights into the structural dynamics of a number of systems and processes, including colloidal suspensions or gels 7,8 , ferro-fluids, ferromagnets and ferroelectrics 9–11 , polymeric glasses 12 , diffusion in crystalline alloys and phase transformations 13,14 , or aging in MGs 15–21 . Common to many of these studies is the use of a stretched exponential function that phenomenologically describes the relaxation behavior, via both the relaxation time τ and the stretching exponent β .…”