Fabrication, characterization, and magnetic properties of exchange-coupled porous BaFe8Al4O19/Co0.6Zn0.4Fe2O4 nanocomposite magnets

Abstract

Fabrication of exchange-coupled nanocomposite magnets has been considered to be the most effective method to achieve the high energy product for advanced permanent magnet applications. In this work, we report a facile auto-combustion synthesis to prepare porous exchange-coupled hard–soft ferrite-based magnetic BaFe₈Al₄O₁₉−x wt% Co_0.6Zn_0.4Fe₂O₄ nanocomposites (where x = 10, 20, 30 and 40), which realize an effective exchange-coupled interaction when the x value is less than 30. Compared with BaFe₈Al₄O₁₉, the optimized nanocomposite with 20% Co_0.6Zn_0.4Fe₂O₄ shows a 70.3% increase in M_s and a 60.4% enhancement in M_r and maintains a high H_c value of 8.8 kOe. The work demonstrates that the auto-combustion synthesis is a promising approach for the fabrication of high-performance ferrite-based permanent magnets.