Local structure around Co in (Zn, Co)O nanoparticles

We have got the conclusion that Zn_1-xCo_xO (x=0.01, 0.03) samples prepared by sol-gel method were both room temperature ferromagnetic in this study before, and it was found by structural analysis that there was no secondary phase existing except Co₃O₄.We also owned the FM to the F center model as the result of the proof of O vacancy. In this paper, we have made a further study of the extended x-ray absorption fine structure (EXAFS) spectrum to get a picture of the local structure around Co ions. The χ(k) function of Co K-edge EXAFS were analyzed by adding kinds of Co structures to fit the experimental dates. Substitutional Co and Co of impurity Co₃O₄ were the first considered factors. The possible contribution of Co in F center model (Co-O vacancy-Co) was also considered.