Structural and magnetic properties of SrFe12O19 hexaferrite synthesized by a modified chemical co-precipitation method

Structural and magnetic properties of nanocrystalline BaFe12O19 synthesized by microwave-hydrothermal method

“…The morphology of the grains is found to be in hexagonal shape (plate like). This type of shape was observed for hydrothermal process (Lin et al 1990;Liu et al 1999;Zi et al 2008). For the samples sintered at 750 and 850°C, over the plate-shaped grains some spherical grains are observed which are attributed to the intermediate nonmagnetic phases of barium hexaferrites which can be clearly observed in XRD patterns (Fig.…”

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

“…It was observed that all samples showed a change in the hysteresis loops, showing the typical behavior of a hard magnetic phase that corresponded to SrFe12O19, confirming that the reaction for obtaining the hexagonal SrFe12O19 was completed. The powders obtained from the 1173 K had a specific magnetization value below the values reported for strontium hexaferrite [4,13,18], this was due to the presence of secondary phases (SrFeO2.5, α-Fe2O3, Fe2O3) in the strontium hexaferrite that distort the collinear arrangement of parallel spin, therefore, it is known that the value of Ms in the SrFe12O19 is determined by the distribution of Fe 3+ ions in five All annealed powders showed Perminvar hysteresis loops (also known as "wasp waist"), and were more noticeable in the material synthesized at 180 W, which showed an unexpected low coercivity of 2.31 × 10 4 A/m. These types of hysteresis loops are associated with the antiferromagnetic coupling of hard and soft magnetic phases, in this case, SrFe 12 O 19 and SrFeO 2.5 , respectively [29].…”

“…Increasing the temperature of the heat treatment to 1173 and 1323 K presented the hysteresis loops M(H) shown in Figure 7c, 4 A/m from the thermal treatment at 1323 K. Additionally, this powder had a decrease in the coercive field, which was due to the small D (56.81 nm) confirmed by SEM, where this value was below the critical radius of the hexaferrite (367.22 nm). This value separates the transition of a monodomain state to a magnetic multidomain [13].…”

“…The hexagonal ferrite type-M is denoted by the formula MFe 12 O 19 , where M is a divalent metal ion, typically Sr 2+ , Ba 2+ , or Pb 2+ [2]. Since its discovery in 1950 [3], the hexagonal ferrite type-M SrFe 12 O 19 has played an important role in hard magnetic materials and has been studied for decades due to its good chemical stability, ferrimagnetic behavior, high Curie temperature, high saturation magnetization, high coercivity, high magneto-crystalline anisotropy (MCA), and it is inexpensive compared to similar compounds [4][5][6]. As it has magnetization values of about 60 Am 2 /kg and coercivity of 4.37 × 10 5 A/m, it is widely used in magnetic recording material, data storage devices [7], magneto-optical recordings, microwave devices [8], permanent magnets, and electromagnetic devices [9].…”

Erratum to: Microstructure and Magnetic Properties of SrFe12O19 Nano-sized Powders Prepared by Sol-Gel Auto-combustion Method with CTAB Surfactant

“…Below some critical radius, however, the coercivity decreases and eventually drops to zero since the particles are starting to approach the super paramagnetic behavior [36]. It was reported that the critical particle size for strontium hexaferrite below which the particles have starting to approach the super paramagnetic behavior is about 40-60 nm [31,37], and the maximum critical particle size for strontium hexaferrite single domains is reported to be about 650 nm [38]. According to FESEM image of the sample synthesized without CTAB addition, the particle size is lower than the critical single-domain size while there are some particles that approached to the super paramagnetic behavior.…”