Transport properties of the metallic two-dimensional triangular antiferromagnet Ag2CrO2

We have investigated the magnetotransport properties of polycrystalline samples of Ag2CrO2, which is a metallic two-dimensional triangular antiferromagnetic compound (T-N similar to 24 K). The electrical resistivity of this compound displayed metallic behavior and an abrupt decrease at T-N. Below T-N, almost linear positive magnetoresistance was observed. On the other hand, just above T-N, a large negative magnetoresistance of -38% at 8 T was observed. The absolute value of the negative magnetoresistance decreases with increasing temperature. The Hall resistance showed a nonlinear behavior as a function of the magnetic field below T-N. These results suggest that the transport properties of Ag2CrO2 are closely related to its unusual antiferromagnetic spin-structure.