Transport properties in filled skutterudite GdRu₄P₁₂

We have investigated the Hall effect in GdRu₄P₁₂ for the first time. From the temperature and magnetic field dependences of the Hall effect along with the magnetoresistance, we evaluated the change in carrier density across the antiferromagnetic (AF) transition accompanied by the Fermi surface reconstruction. About one tenth of carriers remain in the AF phase, in contrast with PrRu₄P₁₂ where most of the carriers disappear in the ordered phase. The anomalous part of Hall coefficient in GdRu₄P₁₂ is smaller than those in the PrRu ₄P₁₂ and PrFe₄P₁₂, which is consistent with the well localized nature of 4f electrons.