Structural, Microstructural and Magnetic Performance of NdFeB/Ni-Zn Ferrites Hybrid Magnetic Composites

Hybrid magnets integrate permanent and soft magnetic materials, resulting in enhanced magnetic performance suitable for a variety of applications. Neodymium-iron-boron (NdFeB) magnets, known for their high energy output, exhibit limitations at elevated frequencies due to eddy current effects. To address this problem, it is beneficial to combine NdFeB with high-resistivity nickel zinc ferrites (NZF) to optimize their magnetic properties. This study focuses on the synthesis of NZF and the fabrication of NdFeB/NZF hybrid composites with varying ratios of NdFeB-to-NZF (40:60, 50:50, and 60:40) and different configurations. Their structural, microstructural, and magnetic characteristics were analyzed to identify the optimum fraction for the hybrid composite formulations. In this work, a commercially available NdFeB and NZF were synthesized via high-energy ball milling while NdFeB was used for the composite’s fabrication. Among the synthesized samples, the mixture-composites of a 60:40 ratio exhibited the highest saturation magnetization of 43.01 emu/g with a notable Curie temperature of 390 °C. The results indicate that increasing the hard phase of NdFeB enhances both saturation magnetization and Curie temperature in all composite samples. Conversely, the stacked-composites with a 40:60 ratio displayed the highest resistivity at 7.96x10 6 Ωm, suggesting that a higher proportion of NZF significantly contributes to increased resistivity. The observed enhancements in magnetic properties can be attributed to the exchange spring mechanism between the soft and hard magnetic phases, as well as the larger grain size in the samples, which promotes a greater number of magnetic domains and reduction of the grain boundaries. Thus, it facilitates more efficient domain wall movement in response to the external magnetic field.