CeNiAsO: an antiferromagnetic dense Kondo lattice.

A cerium-containing pnictide, CeNiAsO, crystallized in the ZrCuSiAs-type structure, has been investigated by measuring transport and magnetic properties, as well as specific heat. We found that CeNiAsO is an antiferromagnetic dense Kondo lattice metallic compound with Kondo scale T(K) ∼15 K and shows an enhanced Sommerfeld coefficient of γ(0) ∼203 mJ mol K(-2). While no superconductivity can be observed down to 30 mK, Ce ions exhibit two successive antiferromagnetic (AFM) transitions. We propose that the magnetic moment of the Ce ion could align in the G-type AFM order below the first transition at T(N1)=9.3 K, and it might be modified into the C-type AFM order below a lower transition at T(N2)=7.3 K. Our results indicate that the 3d-4f interlayer Kondo interactions play an important role in Ni-based Ce-containing pnictides.