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FM: Fachverband Funktionsmaterialien
FM 14: Focus Session: Materials Research in Polar Oxides – From Domain Engineering to Photonic and Electronic Devices II
FM 14.2: Vortrag
Mittwoch, 11. März 2026, 15:15–15:30, BEY/0138
Strain Driven Ferroelastic Switching and Barkhausen Type Behavior in LaAlO3 — •Vladyslav Kovtunovych, Matthias Roeper, Lukas M. Eng, and Samuel D. Seddon — Institut für Angewandte Physik (IAP)- Nöthnitzer Str. 61, 01187 Dresden
Lanthanum aluminate (LaAlO3; LAO) is an oxide perovskite widely used in nano-electronics, and frequently employed as a thin-film substrate therein due to its convienient lattice match to many multiferroic and/or ferroelectric materials. Although oftentimes overlooked, LAO is an improper ferroelastic, posessing crystallographic domains delineated by twin walls, responding to the global application to strain akin to ferromagnetic or ferroelectric materials to magnetic or electric fields respectively. This study focuses on twin wall motion, which was induced and recorded using a commercial Razorbill strain cell with a high-resolution capacitive sensor. Measurements of LaAlO3 under increasing uniaxial compression, revealed the expected jerky domain wall motion indicative of Barkhausen noise, the stochastic stepped reordering of local ordering parameters common among all ferroic materials. This scale invariant physics acts as a power law governing all length scales, from avalanches on mountains down to the nanoscale. Complementary XRD measurements of the expected Bragg peak splitting are correlated with polarised light microscopy imaging all as a function of lattice strain, to observe this effect in a whole new light.
Keywords: ferroelasticity; domain wall dynamics; LaAlO$_3$; uniaxial strain