We fabricated 100 nm thick films of two-dimensional triangular antiferromagnet Ag2CrO2 using the mechanical exfoliation technique, and performed the transport measurements down to 5 K. As in the case of polycrystalline samples, a large reduction of the resistivity due to the antiferromagnetic ordering was clearly observed at around 25 K. Surprisingly, the resistivity for the thin films is one order magnitude smaller than that for the polycrystalline samples, indicating that the crystalline nature is much better in the former than in the latter. The present result sheds new light on the use of atomic-layer antiferromagnetic materials for device applications.
