Avalanche criticality in LaAlO 3 and the effect of aspect ratio

John J. R. Scott, Blai Casals, King-Fa Luo, Atta Haq, Davide Mariotti, Ekhard K. H. Salje, Miryam Arredondo

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Abstract

Ferroic domain dynamics, as a function of external stimuli, can be collectively described as scale-invariant avalanches characterised by a critical exponent that are sensitive to the complexity of the domain microstructure. The understanding and manipulation of these avalanches lies at the heart of developing novel applications such as neuromorphic computing. Here we combine in situ heating optical observations and mean-field analysis to investigate the collective domain behaviour in pure-ferroelastic lanthanum aluminate (LaAlO3) as a function of aspect ratio, the ratio of sample length to width, where the movement of the domains is predominantly driven by thermal stresses via thermal expansion/contraction during heat cycling. Our observations demonstrate that the aspect ratio induces (1) distinctive domain microstructures at room temperature, (2) a deviation of dynamical behaviour at high temperatures and (3) critical exponent mixing in the higher aspect ratio samples that accompanies this behaviour. While the critical exponents of each aspect ratio fall within mean-field predicted values, we highlight the effect that the aspect ratio has in inducing exponent mixing. Hence, furthering our understanding towards tuning and controlling avalanches which is crucial for fundamental and applied research.
Original languageEnglish
Article number14818
Pages (from-to)1-9
Number of pages9
JournalScientific Reports
Volume12
Issue number1
Early online date1 Sep 2022
DOIs
Publication statusE-pub ahead of print - 1 Sep 2022

Bibliographical note

Funding Information:
The authors acknowledge the support from the EPSRC EP/N509541 grant. We thank Dr. Raymond McQuaid for his advise and input towards this publication.

Publisher Copyright:
© 2022, The Author(s).

Keywords

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  • /639/301
  • /639/766
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