Preparation and magnetic properties of Sm–Co doped strontium ferrite

:In this work, Sm–Co doped strontium ferrite, SrFe12-xSmxCoxO19 (x = 0·1–0·5) composites were prepared by adding Sm3+ and Co2+ cations into M-type strontium ferrite using one-step chemical coprecipitation method. The composites were characterized by FTIR and XRD. The magnetic properties of the samples were measured and analyzed by VSM. The results indicated that the average crystallite sizes located in a range of 29·7–32·9 nm. Lattice constants, a and c were close to 5·88 and 23·05 Å for the M-type strontium ferrite phase. The analyses of magnetic properties demonstrated that when x = 0·2 and 0·4, Sm3+ and Co2+ ions substituted Fe3+ ions at 12 k (↑) or 2a (↑) site. While, as x = 0·1, 0·3, and 0·5, Fe3+ ions at 12 k (↑) or 2a (↑) site were replaced by Sm3+ ions and Fe3+ ions at 4f2 (↓) site were substituted by Co2+ ions. Meanwhile, the proposed substitute mechanism in this work was expected to provide a good concept to modify directionally M-type strontium ferrite in order to extend its application field.