Effect of gallium doping on electromagnetic properties of barium hexaferrite

The BaFe12.5GaxO3.9 (x <= 1.2) hexaferrites were synthesized by the usual ceramic technology. It was been established that with the x increase the unit cell and magnetic parameters monotonically decrease. The frequency of natural ferromagnetic resonance firstly decreases from 49.6 GHz down to 49.1 GHz when x = 0.6 and then it increases up to 50.5 GHz. The line width monotonically increases from 3.5 GHz up to 5 GHz. The peak amplitude of resonant curve changes slightly with the exception for the x = 0.9 when it reaches -16 dB. The 1.3 GHz/kOe frequency shift in bias field is more intensive for small x = 0.3. The decreasing of the magnetic parameters is a result of the dilution of the Fe3+ - O2- - Fe3+ superexchange interactions. The behavior of the amplitude frequency characteristics is largely determined by the reduction of the uniaxial exchange anisotropy. The prospects of the Ga-substituted hexaferrites as a material effectively absorbing the high-frequency electromagnetic radiation are shown.