SP Seminar 30.05.2016 @SISSA: Foini (MONDAY)

[Condensed Matter Section]

JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR

Monday May 30 - 11:00 a.m.

SISSA, room 128


*****************************************************************
Speaker:  Laura Foini

Title: Spatio-temporal patterns in ultra-slow domain wall creep dynamics.

Abstract: In presence of impurities, ferromagnetic and ferroelectric
domain walls slide only above a finite external field. Close to this
depinning threshold, the wall proceeds by large and abrupt jumps,
called avalanches, while, at much smaller field, it creeps by thermal
activation.
In our work  we developed a novel numerical technique that captures
the ultra-slow creep regime over huge time scales, allowing us to
access the regime of very low force and temperature.
Thanks to this technique we point out the existence of activated
events that involve collective reorganizations similar to avalanches,
but, at variance with them, display correlated spatio-temporal
patterns that recall the complex sequence of aftershocks observed
after a large earthquake.
   Remarkably, we show that events assembly in independent clusters
owning the same scale-free statistics as critical depinning avalanches.
   This correlated dynamics should be experimentally accessible by
magneto-optical imaging of ferromagnetic films.

*****************************************************************