Figure 8: (a) A plot of anomalous Hall resistivity, , against , measured in a field of 0.3 T along the [111] direction of Pr2Ir2O7 single crystals. A clear increase is seen below K before exponential growth below the Weiss temperature, K. The inset shows the reverse behaviour for the ordinary Hall coefficient, , under the same conditions. The figure is taken from [9]. (b) Field-dependence of the anomalous Hall resistivity, , with the field applied along the (a) [111], (b) [110], and (c) [100] directions of Pr2Ir2O7 single crystals. The pronounced hysteresis along the [111] direction, suggested to host the “3-in, 1-out” spin structure, is severely reduced along [110] and [100] due to the stabilisation of the “2-in, 2-out” structure. Figure from [12].