Magnetic and structural properties of BaFe12−xGaxO19 nanoparticles

The structural and magnetic properties of barium hexaferrite nanoparticles (BaFe12−xGaxO19) with x = 0.0–1.0, prepared by ball milling were investigated using XRD, TEM, and VSM. It was found that the particles and crystallites have similar mean size of ∼41 nm for all investigated samples. The saturation magnetization decreased slightly and nonlinearly with increasing x, and this was attributed to different preferential site occupation of Ga at low and high concentration ranges. The coercivity decreased slightly with increasing x for low concentrations of Ga (x ≤ 0.2), and then increased with increasing Ga concentration up to x = 1.0. This behavior of the coercivity was attributed to the change in the exchange coupling, which was confirmed by the variation of SFD, remanence ratio and Curie temperature with Ga concentration in the samples.