Factors Affecting the Synthesis and Formation of Single-Phase Barium Hexaferrite by a Technique of Oxalate Precursor

Abstract

Problem statement: Barium hexaferrite (BaFe₁₂O₁₉), is of great importance as permanent magnets, particularly for magnetic recording as well as in microwave devices. Approach: The aim of this study was to synthesize Stoichiometric and single-phase barium hexaferrite through a technique of oxalate precursor. Effects of different Fe³⁺/Ba²⁺ mole ratio and annealing temperature on the particle size, microstructure and magnetic properties of the resulting barium hexaferrite powders has been studied and reported in the presented research. The annealing temperature was controlled from 900-1200°C, while the Fe³⁺/Ba²⁺ was controlled from 12-8.57. Results: The resultant powders were investigated by Differential Thermal Analyzer (DTA), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). Single phase of well crystalline BaFe₁₂O₁₉ was first obtained at Fe³⁺/Ba²⁺ mole ratio of 9.23 and 8.57 at annealing temperature 1100°C. Moreover, at annealing temperature 1200°C the single phase BaFe12O19 appeared at all different Fe³⁺/Ba²⁺ mole ratio. The SEM results showed that the grains were regular hexagonal platelets. In addition, maximum saturation magnetization (70.25 emu g^-1) was observed at mole ratio 10 and annealing temperature 1200°C. However, it was found that the coercivety of the synthesized BaFe₁₂O₁₉ samples were lower than the theoretical values. Conclusion: The barium hexaferrite was synthesized at annealing temperature 1200°C with a single phase using oxalate as precursor route.