The Physical Properties Of Isomers Of Sr₂FeCoO₆

Using density-functional calculations within the generalized gradient approximation (GGA)+U framework, the effect of disorder on the special physical properties of the double perovskite oxide Sr2FeCoO6. The calculated results show that:(1)For the ordered double perovskite oxide Sr2FeCoO6, it has the same magnetic moments on four Fe and four Co sites of 4.01μB and 1.97μB, respectively. Sr2FeCoO6 shows half-metallic ferromagnetism at low temperature. There are a few up-spin density of states near the Fermi energy level, while no down-spin density of states is around the Fermi energy level with a energy gap of about 0.8 eV.(2)For the disordered double perovskite oxide Sr2FeCoO6, the physical properties is in relation to the degree of disorder of Fe and Co ions. The magnetic moments on the Fe sites are influenced by the number of Co ions on the nearest-neighbor sites of Fe, and decrease with the decrease of the number of Co ions. However, the performance of Co is contrast to that of Fe. Furthermore, the consequence of the mis-site disorded Sr2FeCoO6 is a decrease of the down-spin energy gap from 0.8 eV to 0.2 eV, and lastly, the down-spin energy gap collapses which cause the disappear of the half-metallic ferromagnetic nature.