Achieving ferromagnetism in single-crystalline bismuth ferrite nanoparticles through jet milling

Bismuth ferrite, a multiferroic material known for its associated ferroelectric and antiferromagnetic properties, holds significant potential for advanced applications in memory devices, sensors, and electrocatalysts. However, achieving a simultaneous increase in both magnetization and coercivity while preserving the material’s single-crystallinity has been a considerable challenge, especially in phase-pure bismuth ferrite. In this work, we synthesized phase-pure BiFeO₃ nanoparticles using the sol–gel method and subjected them to jet milling at varying pressures. Detailed electron microscopy studies demonstrate that the jet milling process maintains the single-crystalline nature of BiFeO₃ while significantly reducing the particle size. The jet-milled samples exhibited up to a 10 increase in magnetization (~ 10 emu/g) and a 30 times improvement in coercivity (> 1000 Oe) compared to the as-synthesized samples. This enhancement is attributed to the disruption of the cycloidal spin structure due to the reduced crystallite size and reduced agglomeration of the particles. This work presents jet milling as an effective technique for enhancing the magnetic performance of BiFeO₃, with potential applications in multiferroic devices and other advanced technologies.