Séminaire du Professeur Ekhard Salje (FRS) de l’Université de Cambridge le 27 mars 2018 à 14h

Le Labex NanoSaclay a le plaisir d’accueillir dans ses équipes le Professeur Ekhard Salje de l’Université de Cambridge (GB). Celui-ci donnera un séminaire en salle VI.118 (Univers Vivant, 1^er étage) du Bâtiment Eiffel de CentraleSupélec sur le thème : Domain formation and acoustic emission in ferroics: a Progress Report.

Abstract:
Ferroelastic domain boundaries are templates for ferroelectric and ferromagnetic properties located inside domain structures, even when such properties are absent in the bulk. Typical examples are (super-) conducting twin walls in WO3, highly conducting walls in BiFeO3 and in structural interfaces between SrTiO3 and LaAlO3, and ferroelectric walls in CaTiO3. Such functional interfaces may form the base for devices, their development is within the topic of Domain Boundary Engineering.

In this seminar I will focus on the dynamics of the domain boundaries. While Barkhausen noise is well known to most in the ‘ferroics community’ (Barkhausen did his experiments more than 100years ago), the equivalent detection of ‘noise’ in ferroelectrics and of avalanches from changing polarity waves has not been studied systematically before. I will present some examples on simple model systems (BaTiO3) and then show how acoustic emission spectra may be analysed in ferroic materials. I will also mention some martensitic materials where the research is rather advanced, largely because these materials are essential for medical applications such as implants used in heart bypasses etc.

Contacts :

• nick.barrett@cea.fr
• stéphane.fusil@cnrs-thales.fr
• brahim.dkhil@centralesupelec.fr