Disorder-induced microscopic magnetic memory
  Using coherent x-ray speckle metrology, we have measured the influence of disorder on major loop return point memory (RPM) and complementary point memory (CPM) for a series of perpendicular anisotropy Co/Pt multilayer films. In the low disorder limit, the domain structures show no memory with field cycling--no RPM and no CPM. With increasing disorder, we observe the onset and the saturation of both the RPM and the CPM. These results provide the first direct ensemble-sensitive experimental study of the effects of varying disorder on microscopic magnetic memory and are compared against the predictions of existing theories. 
M.S. Pierce, C.R. Buechler, L.B. Sorensen, J.J. Turner, S.D. Kevan,   E.A. Jagla, J.M. Deutsch, T. Mai, O. Narayan, J.E. Dav...