The key feature defining ferroic materials is the hysteretic behaviour of their order parameter under an external field. Switching is a consequence of collective field-induced domain wall displacements that occurs through scale invariant jumps with avalanche characteristics. In some materials the domain walls exhibit completely different properties respect to the bulk, such superconductivity in non-superconductors, magnetism in non-ferromagnets, or polarization in non-polar materials. When the active elements of a device are the domain walls themselves, creating, erasing and moving them in a controlled way becomes crucial. My research is focused on two main lines: first, on the study of the avalanches features during the switching process. In this direction we found a correlation between the avalanche energy critical exponents and the Hausdorff dimension of the shape of the switched regions of ferroelectric materials [1]. Secondly, we explore strategies to modify reversibly the avalanche distributions. Using surface acoustic waves as field perturbations [2], we tune the switching behaviour of ferromagnetic thin films, controlling the domain wall position at the micron scale.    

[1] B. Casals, G. F. Nataf and E. K.H. Salje. Nat. Commun. 12, 345 (2021).  

[2] B. Casals, N. Statuto, M. Foerster, A. Hernandez-Minguez, R. Cichelero, P. Manshausen, A. Mandzia, L. Aballe, J. M. Hernandez and F. Macia. Phys. Rev. Lett. 124, 137202 (2020)