Effects of partial Co replacement by Fe in Sr_0.775Y_0.225CoO_3-δ on its magnetic property, oxygen deficiency and crystal structure

A study has been conducted on the effects of partial, 10 % Co substitution by Fe in the perovskite Sr_0.775Y_0.225CoO_3-δ compound. The XRD data show that the resulted samples of Fe-free and Fe-doped compounds exhibit good 314 single phase quality with a tetragonal I4/mmm crystal structure. The measured M-T curves display the typical feature of ferromagnetic (FM) transition at 335 K for the Fe-free sample, while showing significantly degraded FM ordering for the 10 % Fe-doped sample. The oxygen deficiency determined fro|m our 10 % Fe doped sample is found to decrease by only 0.025. Further detailed analysis of the XRD data also reveals distinctly different structural changes in the Co-O slabs compared to the 50 % Fe-doped sample which exhibits a complete suppression of FM order. The results of this study, thus, have revealed the close relations among the changes induced by Fe doping in the magnetic ordering of crystal, and its oxygen content as well as the associated local structure in the Co-O layers responsible for the magnetic properties in the compound.