Spin-state transition of Co ion (25/2) in hole substituted 1D chain of CaCoO.

We have discovered spin-state transition (= 2 to= 5/2) of Co ions due to Mg substitution in the CaCoOapparent in the magnetic susceptibility, x-ray photoelectron spectroscopy (XPS), and first-principles study. We also examine the effect of Mg substitution on the magnetic and electronic structure of CaCoOby first-principles calculations. It involves generalized gradient approximation with Coulomb interaction () in exchange-correlation energy functional.