Crystal structure, magnetic, and microwave properties of solid solutions BaFe$_{12-x}$Ga$_{x}$O$_{19}$ (0.1 $\le x\le$ 1.2)

The crystal structure of solid solutions of an $M$-type hexagonal barium ferrite BaFe$_{1-x}$Ga$_{x}$O$_{19}$ ($x$ = 0.1–1.2) with the isostructural diamagnetic substitution of Ga$^{3+}$ ions has been studied by X-ray diffraction. The unit cell parameters have been calculated for all compositions. The field and temperature dependences of the specific magnetization of these solid solutions have been measured by vibrational magnetometry. The microwave properties of BaFe$_{12-x}$Ga$_{x}$O$_{19}$ ($x$ = 0.1–1.2) have been studied in a bias field. It has been shown that the frequency of natural ferromagnetic resonance decreases as the Ga concentration increases from $x$ = 0.1 to $x$ = 0.6 and it increases once again as the Ga concentration increases to $x$ = 1.2. As the Ga concentration increases, the natural ferromagnetic resonance lines broaden. This indicates an increase in the frequency range of strong absorption of electromagnetic radiation. In this case, the amplitude of the resonance curve peak changes insignificantly. The frequency shift of the natural ferromagnetic resonance in an external magnetic field increases as the gallium ion concentration in the sample decreases.