Anisotropic hysteretic Hall-effect and magnetic control of chiral   domains in the chiral spin states of Pr$_2$Ir$_2$O$_7$
  We uncover a strong anisotropy in both the anomalous Hall effect (AHE) and the magnetoresistance of the chiral spin states of Pr$_2$Ir$_2$O$_7$. The AHE appearing below 1.5 K at zero magnetic field shows hysteresis which is most pronounced for fields cycled along the [111] direction. This hysteresis is compatible with the field-induced growth of domains composed by the 3-in 1-out spin states which remain coexisting with the 2-in 2-out spin ice manifold once the field is removed. Only for fields applied along the [111] direction, we observe a large positive magnetoresistance and Shubnikov de Haas oscillations above a metamagnetic critical field. These observations suggest the reconstruction of the electronic structure of the conduction electrons by the field-induced spin-texture. 
L. Balicas, S. Nakatsuji, Y. Machida, and S. Onoda
cond-mat.str-el