Creep and depinning of elastic interfaces in Random Media

A. B. KOLTON

S. C. de Bariloche

Conferencia; Advanced Topics in Magnetism and Superconductivity AToMS-2014; 2014

Centro Atómico Bariloche

Many physical phenomena such as magnetic and ferroelectric domain walls motion, fluid invasion in porous media, moving contact lines in wetting, crack propagation, as well as the motion of vortex lines in type II superconductors, charge density waves, or Wigner crystals of classical particles or of electrons, involve the displacement of elastic object or interface in a weakly disordered medium. How the velocity of motion depends on the driving force f poses important fundamental questions and is also of prime importance in the use of the host materials. In the absence of disorder, or for a large f, motion is limited by dissipation and the interface moves in a flow regime, with a velocity essentially proportional to f. However, in real materials the presence of disorder leads to pinning which dramatically modifies the response to the force, leading to the ultra-slow nonlinear regimes of creep and depinning. I will present novel theoretical results describing such non trivial regimes, and compare it with very recent experiments on magnetic field-driven domain wall motion in an ultrathin Pt/Co(0.45nm)/Pt ferromagnetic film with perpendicular anisotropy, over a wide temperature and field range.