Micromagnetic Study on Nd₂Fe₁₄B/α-Fe Nanocomposite with Inter-Granular Phase

Permanent magnetic materials are essential functional materials for electric motors, generators, and home appliances. The magnetic performance of hard-/soft-phase nanocomposites depends on their microstructure. Nanocomposites with an inter-granular phase, fabricated via a physical route, are fascinating as they can further enhance the magnetic properties of hard-/soft-phase nanocomposites. In this study, the magnetic performance is estimated on an isotropic Nd₂Fe₁₄B/α-Fe nanocomposite system with an inter-granular phase via micromagnetic simulation. The simulated micromagnetic model of an isotropic Nd₂Fe₁₄B/α-Fe nanocomposite with the inter-granular phase of α-Fe is shown in Fig. 1.

FIG. 1. Micromagnetic model of an isotropic Nd₂Fe₁₄B/α-Fe nanocomposite with an inter-granular phase of α-Fe

The simulated results show that the magnetic performance of the system is strongly dependent on the size of Nd₂Fe₁₄B particles and the thickness of α-Fe phase

FIG. 2. Variation in coercivity(left), remanence(middle) and energy products(right) as a function of the size of Nd–Fe–B particles at various thicknesses (5–20 nm) of α-Fe phase

Due to a strong exchange coupling between the hard magnetic Nd–Fe–B and the soft magnetic α-Fe, the remanence is strongly influenced by saturation magnetization.

FIG. 3. Hysteresis loops at various sizes of Nd–Fe–B particles at (a) 5 nm and (b) 10 nm thicknesses of α-Fe phase

Figure 4 shows a typical magnetization change in the hard/soft magnetic phase nanocomposite system with decreasing external magnetic field, for 10 nm α-Fe and 50 nm Nd–Fe–B. The reversal occurs first with the α-Fe phase located on the surface of the system and then proceeds from the surface to the inside along the inter-granular phase and finally to the Nd–Fe–B particles.

FIG. 4. Magnetization reversal of the nanocomposite system with 10 nm α-Fe and 50 nm Nd–Fe–B

We conclude that isotropic Nd₂Fe₁₄B/α-Fe nanocomposites with an inter-granular phase can exhibit enhanced magnetic performance with small thicknesses of the α-Fe phase. Our results were published in the SCI International Journal "AIP Advances"(13 (2023) 085201) under the title of the "Micromagnetic study on Nd₂Fe₁₄B/α-Fe nanocomposite with inter-granular phase"(https://doi.org/10.1016/5.0151976).