Preparation of unsintered spherical BaFe12O19 nanoparticles via an alcohol-assisted spray-pyrolysis route

Unsintered spherical barium ferrite (BaFe12O19) nanoparticles were successfully prepared by the alcohol-assisted spray-pyrolysis (AASP) method without any postannealing processes. Ethyl alcohol (EtOH) in the precursor solution for BaFe12O19 particles was very effective not only in its capacity to decrease the particle size, but also in enhancing crystallization into barium ferrite hexagonal phase. As the vol% of EtOH increased from 0 to 20, a decrease of particle size from 136 to 111 nm and an increase of crystallinity were clearly observed. The AASP method was optimized by adjusting the chemical concentration in the precursor solution, and finally, unsintered spherical BaFe12O19 particles, with a geometric mean diameter of 72 nm, a geometric SD of 1.4, and an intrinsic coercivity of 4510 Oe, were successfully prepared.