Mössbauer studies of hexagonal isotropic polycrystalline ferrites SrFe$_{12}$O$_{19}$ obtained by radiation-thermal sintering

Hexagonal strontium ferrite (SrFe$_{12}$O$_{19}$) is widely used as permanent magnets and in microwave electronics. Its high characteristics are distinguished by production technologies. In this work, the method of radiation-thermal sintering (RTS) in a fast electron beam at the ILU-6 accelerator was used for SrFe$_{12}$O$_{19}$ samples. The process temperature was from 1200$^\circ$C to 1400$^\circ$C, the sintering time was from 10 to 90 minutes. The phase composition and crystal lattice parameters of the samples were studied using Mössbauer spectroscopy and X-ray diffraction. Mössbauer spectra were recorded on an MC1104E spectrometer, X-ray diffraction – on a DRON-8 diffractometer. The density of the structure was achieved by the Archimedes method on an UW620H electronic balance. The results show that all transistors are single-phase and have the space group P63/mmc (No. 194), which corresponds to the hexagonal ferrite sequences. The optimal parameters for the synthesis of isotropic hexaferrites are a temperature of 1250–1300$^\circ$C and a process duration of 30–60 minutes. Thus, RTS can serve as an alternative product for obtaining polycrystalline isotropic hexagonal ferrite SrFe$_{12}$O$_{19}$, demonstrating high energy efficiency and cost-effectiveness compared to conservative methods.