Temperature evolution of the structure parameters and exchange interactions in BaFe12−xInxO19

Indium doped barium hexaferrites were synthesized by usual ceramic technology. They were investigated by the high resolution neutron powder diffraction and vibration sample magnetometry in temperatures up to 730 K. Analysis of NPD data was performed by FullProf in classical approximation. Structure parameters as well as bond lengths and bond angles were determined versus the substitution level and the temperature. Main attention was paid to the distribution of indium cations between different crystallographic positions and temperature change of bond lengths and bond angles. Effect of these two structure parameters on Fe3+(i) - O− - Fe3+(j) (i, j = 1, 2, 3, 4, 5) indirect superexchange interactions with the substitution level and temperature was established. A dominant effect of a positive intrasublattice Fe3+(i) - O2− - Fe3+(i) (i = 1, 2, 3, 4, 5) indirect superexchange interactions on a magnetic ordering was detected.