Itinerant Nature of Ce in CeCo₅

Due to the high uniaxial anisotropy and abundant nature of Ce, CeCo₅ has attracted the attention of scientists for developing an excellent permanent magnet. Here, we discuss the itinerant nature of Ce in CeCo₅ using density functional theory (DFT). Ce based intermetallic compounds show interesting magnetism because of the mixed-valence 4f state. The 3+ valence would have provided 1.0 µ_B/Ce 4f; however, in either case with and without employing on-site electron correlation parameter, we obtain 4f spin moment less than 1.0 µ_B/Ce 4f. Also, the 3d-5d hybridization in CeCo₅ is strong enough to overlap 4f states below the Fermi level and form a 3d-5d-4f hybridization thereby indicating the itinerant nature of Ce 4f in CeCo₅. This assessment allows us to consider CeCo₅ as an itinerant magnetic material system suitable to treat by standard DFT. Further, the 4f spin moment of CeCo₅ is partially canceled by the orbital counterpart and the Co moment is reduced by the stronger 3d-4f hybridization in the spin-down channel.