  We study the Hall and Nernst effects across the antiferromagnetic transition
that reconstructs the quasi-2D Fermi surface of the metallic local moment
antiferromagnet PdCrO$_2$. We show that non- monotonic temperature dependence
in the Hall effect and a sign change in the Nernst effect above the ordering
temperature cannot be understood within a simple single-band transport model.
The inclusion of coherent scattering by critical antiferromagnetic fluctuations
can qualitatively account for these features in the transport coefficients. We
discuss the implications of this for the pseudogap phase of the cuprate
superconductors, which have a similar Fermi surface and where the same
transport signatures are observed.
