Figure 7: (a) Zero-field-cooled/field-cooled temperature dependence of the Hall conductivity (left axis) and magnetic susceptibility (right axis), measured in a field of  T along the [111] direction of Pr2Ir2O7 single crystals. Bifurcation of at occurs above any magnetic ordering temperature observed in . (b) Zero-field temperature dependence of and magnetisation, . A spontaneous Hall conductivity occurs at in the absence of any magnetic moment, which does not appear until below . Figures are from [6]. (c) The induced Ir spin structures from the “2-in, 2-out” and “3-in, 1-out” Pr tetrahedra in Pr2Ir2O7, taken from [4]. (d) Calculated -dependence of the anomalous Hall coefficient for various spin structures in Pr2Ir2O7, using the SK hopping integrals shown. The nonzero values obtained at and , where the spin chirality term is zero, indicate that the spin chirality mechanism is not the dominant mechanism, taken from [4].