Figure 5: Monopole and dipole signatures revealed by comparing the measured adiabatic (
) and isothermal (
) susceptibilities.
) and isothermal (
) susceptibilities.From: Brownian motion and quantum dynamics of magnetic monopoles in spin ice
(a) the susceptibilities are shown as a function of applied dc field at zero field (black circles) and near the crossover field (grey circles) shown as a red dotted line in Fig. 1. Error bars represent s.d. The full red line is the experimentally measured monopole density fitted to 
by the adjustment of a scale factor (see text). The blue line is a Curie–Weiss law fitted to 
(Supplementary Fig. S4). The light blue line is the theoretical prediction 
(see text). (b) Measured 
as a function of weak applied field 
 
(circles, same colour code is maintained as in Fig. 3). The full red line is the experimentally measured monopole density fitted to 
by the adjustment of a scale factor (see text), also showing the maximum systematic uncertainty (absolute minima maxima) in the measured monopole density (red shading).
