Electrical resistance near the antiferromagnetic transition of dysprosium

The electrical resistance R(T) of a c axis single crystal of dysprosium has been measured in the vicinity of the Neel point TN using a high-precision (8-digit resolution) direct current comparator method. Numerical analysis of the data yields a power law of the form R(T)=A+B epsilon +C epsilon psi in the range 2.5 0, C<0, and psi =0.60. This power law does not extend into the region 0<or approximately=T-TN<or approximately=2.5 K. The breakdown of the power law is consistent with the view that long-range spin fluctuations fail to dominate scattering processes in the immediate vicinity of the Neel point of helical antiferromagnets.