The influence of ambient high pressure to structural features of barium hexaferrite

A comprehensive analysis of the magnetic properties, crystal structure and magnetic configuration of the ceramic BaFe₁₂O₁₉, prepared using the sol-gel method, was conducted over the temperature range from 4 K to room temperature. The impact of ambient pressure on the crystal and magnetic structures of ceramic BaFe₁₂O₁₉has enabled the determination of bulk modulus<i>B</i>₀∼ 123.8 GPa and its first-order derivative<i>B</i>_p' ∼ 4.1, as well as the coefficients of linear compressibility of the lattice parameters for the hexagonal unit cell. The results of neutron diffraction collected at pressures ranging from 0.1 GPa to 5 GPa were analyzed in the framework of both centrosymmetric SG P6₃/mmc (No. 194) and non-centrosymmetric SG P6₃mc (No. 186). The decrease in the total magnetic moment with an increase in ambient pressure was associated with a weakening of the exchange interaction in the ferrimagnetic structure, owing to a reduction in the bond angles (∠ Fe-O-Fe) of various iron sublattices.