Direct Observation of Localized Radial Oxygen Migration in Functioning   Tantalum Oxide Memristors
  Oxygen migration in tantalum oxide, a promising next-generation storage material, is studied using in-operando x-ray absorption spectromicroscopy and is used to microphysically describe accelerated evolution of conduction channel and device failure. The resulting ring-like patterns of oxygen concentration are modeled using thermophoretic forces and Fick diffusion, establishing the critical role of temperature-activated oxygen migration that has been under question lately. 
Suhas Kumar, Catherine E. Graves, John Paul Strachan, Emmanuelle   Merced Grafals, Arthur L. David Kilcoyne, Tolek Tyliszcza...
cond-mat.mtrl-sci cond-mat.mes-hall