Observation of Devil's Staircase in the Novel Spin Valve System   SrCo$_6$O$_{11}$
  Using resonant soft x-ray scattering as a function of both temperature and magnetic field, we reveal a large number of almost degenerate magnetic orders in SrCo6O11. The Ising-like spins in this frustrated material in fact exhibit a so-called magnetic devil's staircase. It is demonstrated how a magnetic field induces transitions between different microscopic spin configurations, which is responsible for the magnetoresistance of SrCo6O11. This material therefore constitutes a unique combination of a magnetic devil's staircase and spin valve effects, yielding a novel type of magnetoresistance system. 
T. Matsuda, S. Partzsch, T. Tsuyama, E. Schierle, E. Weschke, J. Geck,   T. Saito, S. Ishiwata, Y. Tokura, and H. Wadati
cond-mat.str-el cond-mat.mtrl-sci