Discovery of "Devil's staircase" in cobalt oxides



T. Matsuda, T. Tsuyama, T. Saito, S. Ishiwata, Y. Tokura, H. Wadati



Emergence of "Devil's staircase": Anomalous spin ordering revealed by brilliant synchrotron
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.