Study on magnetic role of Bi3+ ion by random cation distribution model in Bi–YIG system

•A sol–gel method is used to synthesis BixY3−xFe5O12 (x=0.0, 0.2, 0.3 and 0.4) system.•The variation of magnetic properties of the samples are explained by increase of exchange interactions and deviation of each sub-lattice direction.•The increase in exchange interaction is attributed to the magnetic role of Bi3+. This role is explained by consider the hybridization of Bi 6p in Fe 3d.•The hyperfine parameters are studied by a random cation distribution model which is based on the variation of the nearest neighbor of ions.

The ambiguous role of bismuth in magnetization behaviour of BixY3−xFe5O12 motivated us to study its structure, magnetic and hyperfine parameters by use of Fourier transform infrared spectroscopy (Far-FTIR), Vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The dependence of hyperfine parameters with the numbers of bismuth ions in the vicinity of iron ion are investigated by a random cation distribution model. The change in vibrational bands broadening in Far-FTIR spectra are studied.