Synthesis and Magnetic Properties of Aligned Strontium Ferrites

Reducing the particle size of hexagonal ferrites is known to increase their coercivity effectively. However, the size reduction also enhances the agglomeration that deteriorates the magnetic alignment of these particles. In this paper, hexagonal plate shape strontium ferrite particles with an average size of 700 nm using a facile salt-assisted ultrasonic spray pyrolysis method were synthesized to increase the coercivity and prevent the agglomeration during calcinations process. Sodium chloride (NaCl) was used as a salt, and the reacted powders were sintered at 1050 °C for 2 h under various oxygen flow rates. With increasing the flow rate of oxygen, the specific saturation magnetization of synthesized strontium ferrite particles increased from 62 to 71 emu/g and the coercivity reached 6000 Oe. Strontium ferrite particles aligned under a magnetic field of about 10 kOe showed that the remanence was 91.85%.