Fig. 3: Spin fluctuations and the specific heat capacity.

a Circles show the low-temperature linear co-efficient of the heat capacity γ calculated using the phenomenological spin-fluctuation model described in the text and our experimentally determined parameters. Solid line is the measured γ of Rost et al.¹⁰. Note the spin-fluctuation model predicts increases of γ approaching B_c and on entering SDW phases A and B. b The measured γ¹⁰ for field values in panel a (fields denoted by colours) plotted against the Brillioun-zone-averaged inverse spin relaxation rate 〈Γ(Q)⁻¹〉. c The measured γ plotted against the experimentally determined 〈Γ(Q)⁻¹〉 for a variety of correlated electron metals^27,28. Solid line is Eq. (3) and ν = 3 for all systems except Sr₃Ru₂O₇ where ν = 1.