Effect of Ga content on magnetic properties of BaFe12−xGaxO19/epoxy composites

The article reports about the effect of Ga content on magnetic properties of 30 wt% BaFe12−xGaxO19/epoxy(x = 0.1, 0.3, 0.6, 0.9 and 1.2) composites with uniform and aligned (due to the action of external magnetic field under preparation) distribution of hexaferrite filler in epoxy matrix. The XRD investigations of BaFe12−xGaxO19/epoxy (x = 0.1, 0.3, 0.6, 0.9 and 1.2) composites have revealed that the alignment degree of a crystalline hexaferrite phase with a hexagonal unit cell of crystal structure and P63/mmc space group in composites with uniform filler distribution is near 0.5 and for the composites with aligned filler distribution it is 1 for the direction along the applied magnetic field and it is 0 for the direction across the applied magnetic field, respectively. The investigation of the hysteresis loops of BaFe12−xGaxO19/epoxy (x = 0.1–1.2) composites with the aligned distribution of filler for both directions to the applied magnetic field has shown that magnetic properties across the alignment direction are superior in comparison with similar measurements taken on composites with uniform filler distribution. It was shown that anisotropy of magnetic properties of BaFe12−xGaxO19/epoxy (x = 0.1–1.2) composites is observed for all the investigated composites with the aligned distribution of the filler. Squareness ratio Ms along/Ms across decreases with Ga content increase, while the value Hc along/Hc across approaches to 1. Such behavior of magnetic characteristics of the investigated composites indicates clearly the decrease in magnetocrystalline anisotropy of Ga-substituted hexaferrite under Ga content increase.