Abstract
A-site-layer-ordered double perovskite YBaCo2O6 with unusually high valence Co3.5+ was found to be an unusual ferromagnetic metal with strong electron correlation. The compound was obtained by topochemically oxidizing the A-site-layer-ordered YBaCo2O5, which contains nominal Co2.5+, in ozone at a low temperature. YBaCo2O6 crystallizes as a fully oxygenated A-site-layer-ordered double perovskite with a tetragonal structure at room temperature and shows an orthorhombic distortion below approximately 140 K. This anisotropic structural distortion induces ferromagnetic ordering of the mixed-valence Co spins with intermediate spin states, suggesting strong spin–lattice coupling in this system. In the ferromagnetic state, the up-spin band mainly consisting of hybridized Co 3d and O 2p crosses the Fermi level, giving the metallic behavior, regardless of the strong electron correlation.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
