In this work, the structural and magnetic characterization of a composite with multifunctional properties is reported, formed from strontium ferrite (SrM) doped with two cations, and polylactic acid (PLA), maintaining a relationship [(1-y)(SrFe12-2xCoxSnxO19) + y (PLA)], for y = 0.0, 0.10, 0.20, 0.30, 0.4, 0.6 and 1.0 and x = 0.0, 0.1 and 0.3. In order to achieve a better interpretation of the experimental data, a phenomenological model of cation distribution is applied. The results suggest the coexistence of both phases independently. For the ferrimagnetic phase, secondary phases of Fe2O3 and CoFe2O4 were detected. The magnetic properties are modulated by the concentrations of the constituent phases and by the nature of the magnetic interactions between them; in addition, these are affected by the entry of the doping elements into the ceramic. The usefulness of the model is demonstrated to predict the distribution of cations in the Fe3+ sites, with the 12k site being the preferential site, which was taken into account and was in good agreement with the analysis of the magnetic properties. Regarding the use of the model in the generalization of the Gorter expression, a good prediction of the behavior of saturation magnetization for the material under study was achieved.