The selected square-wave frequencies at each temperature contain sufficient data to cover a complete Cole-Cole curve and thus accurately characterise the relaxation processes. The isothermal frequency-dependence of the in-phase and out-of-phase susceptibility data were fit to the Generalised Debye model (Eq. 1) in Mathematica to obtain τ Debye and α with good agreement between the fit and the data (Fig. ). The resulting temperature dependence of τ Debye -1 was fitted to: