[en] Full text: Hexagonal ferrite is a class of magnetic material with great scientific and technological interest. The M-type hexaferrites (BaFe₁₂O₁₉) are important ferromagnetic oxides widely used for permanent magnets, magnetic recording media and microwave absorbers. This materials present high resistance to corrosion, large magnetocrystalline anisotropy and as well as large magnetization [1]. In this work, we prepared BaFe₁₂O₁₉ compound by the proteic sol-gel process. This process has been largely applied to synthesize M-type hexaferrite because it uses nitrates as source of metallic ions and in natura coconut water as a complexing agent. Coconut water is rich in proteins and have high content of functional groups containing oxygen which gives to this extender an excellent complexing capacity to anchor metallic species. The nitrates were dissolved in coconut water and calcined to 950 °C/2h. It is shown the X-ray diffraction that indicates the formation of the hexaferrite phase being confirmed by Rietveld refinement and Raman spectroscopy. In addition, it is shown, lattice parameters a, b, c, unit cell volume, average crystallite size, GOF, RP, RWP and Resp, % of BaFe₁₂O₁₉ phase and % of hematite phase, extracted after Rietveld refinement. Magnetization measurement as function of field show a comportment of soft magnetic material. We conclude that the proteic sol-gel route is an excellent low cost route to synthesize M-type barium hexaferrite nanomaterials with soft magnetic characteristics. In addition, the materials can be calcined at temperatures lower than the materials produced by other synthesis routes already found in the literature. References: [1] R.C. Pullar, Hexagonal ferrites: a review of the synthesis, properties and applications of hexaferrite ceramics, Prog. Mater. Sci. 57 (2012) 1191–1334. (author)