Аннотация:We have investigated the influence of substitution of Cr atoms for Fe atoms on the crystal structure, local magnetic and valence states of Fe atoms and parameters of the spatial spin-modulated structure (SSMS) by the 57Fe Mossbauer method in bulk multiferroic BiFe0.80Cr0.20O3 synthesized at high pressures. Measurements were carried out in the temperature range of 5–600 K. The samples had a rhombohedral structure belonging to space group R3c. A cycloid type SSMS model [1] was used in the processing and analysis of our Mossbauer spectra.The temperature dependences of the hyperfine parameters of the 57Fe Mossbauer spectrum – the isomer shift, the quadrupole shift of the spectral components, isotropic and anisotropic contributions to the hyperfine magnetic field and the anharmonicity parameter m of SSMS were obtained and analyzed. It was found the positions of Fe atoms in the first cation coordination sphere of which there were one, two, three and four atoms of Cr. The isotropic contribution to the hyperfine field of the iron atom is decreased when its nearest cation sphere contains chromium atoms. A magnetic phase diagram was constructed in the "anharmonicity parameter m" – "temperature T" axes, indicating the regions of the antiferromagnetic structure of the G-type, anharmonic SSMS with magnetic anisotropy of the "easy axis" and "easy plane" type (see Figure). The paramagnetic state was observed at temperaturc above the Neel point TN = 505 K.