Effect of Sonication Output Power on the Crystal Structure and Magnetism of SrFe12O19 Nanoparticles

Abstract

Abstract:We reported the effect of the sonication output power (SOP), from 120, 180, to 240 W, on the crystal structure, morphology, and magnetic properties of SrFe 12 O 19 nanoparticles synthesized by sonochemical process assisted with heat treatment. X-ray Diffraction analysis of the obtained powder showed the formation of Fe 3 O 4 with low crystallinity degree, which increased with the increase in SOP, together in a crystalline phase identified as SrCO 3 . The formation of SrFe 12 O 19 started at 1073 K, and was completed at 1173 K. However, hexaferrite was obtained with the secondary phases α-Fe 2 O 3 and SrFeO 2.5 . At 1323 K, the secondary phases vanished, and a single phase SrFe 12 O 19 was detected. Vibrating Sample Magnetometry analysis showed that the SrFeO 2.5 phase caused the formation of a hysteresis loop known as the Perminvar magnetic hysteresis loop. At 1323 K, the powder synthesized at 120 W showed a specific magnetization of 67.15 Am 2 /kg at 1.43 × 10 6 A/m, and coercivity of 4.69 × 10 4 A/m, with a spherical-like morphology and average particle size of 56.81 nm obtained by Scanning Electron Microscopy analysis. The increment of SOP promoted a high degree of crystallinity and decrease in crystal size. Additionally, it promoted the formation of secondary phases, induced agglomeration, and modified the morphology of the particles.