Magnetic property and electronic structure of itinerant PdxCoyO2 magnets

The electronic structure of the delafossite-type compound PdCoO2 is calculated by the full potential linear muffin-tin orbital method and the magnetic property of the composition modified (defect injection introduced) compound Pd0.72Co0.68O2 was investigated. The calculation reveals that the density of states of PdCoO2 around the Fermi level is mainly composed of Pd 4d and Co 3d and O 2p orbitals, and the Fermi level is located just at the depression of the density of states. The magnetic nature of the composition modified Pd0.72Co0.68O2 compound is quite complex. The slow spin dynamics found below T-f can be interpreted by considering that the weak ferromagnetic moment in each CoO6 plane is itself disordered. This behavior is explained by the short-range character of the randomness which leads to a finite-size magnetized cluster, and suggests that the presence of these clusters would induce a spin-glass like feature for T<T-f. (C) 2003 American Institute of Physics.