Micromagnetic simulation of microstructure effect for binary-main-phase Nd-Ce-Fe-B magnets

Area of Science:

• Materials Science
• Condensed Matter Physics
• Magnetism

Background:

• Neodymium-iron-boron (Nd-Fe-B) magnets are critical for high-performance applications.
• Chemically heterogeneous binary-main-phase (BMP) magnets offer potential for enhanced magnetic properties.
• Understanding core-shell structures is crucial for optimizing magnet performance.

Purpose of the Study:

• To investigate the magnetic properties of chemically heterogeneous BMP Nd-Ce-Fe-B magnets with a core-shell structure.
• To determine the influence of shell thickness on coercivity and energy product.
• To elucidate the magnetization reversal mechanisms in BMP magnets.

Main Methods:

• Micromagnetic simulations were employed to model the magnetic behavior.
• The study systematically varied Nd-rich shell thickness and Ce concentration.
• Magnetization reversal processes were analyzed at the nanoscale.

Main Results:

• Coercivity exhibits a non-monotonic dependence on Nd-rich shell thickness, with an optimal value for maximum coercivity.
• Significant differences in coercivity and maximum energy product were observed between BMP and single-main-phase magnets.
• Magnetization reversal initiates in Ce-rich shells, followed by Nd-rich cores, with distinct switching behaviors for different grain types.

Conclusions:

• The shell thickness is a critical parameter for optimizing the coercivity of BMP Nd-Ce-Fe-B magnets.
• BMP magnets demonstrate superior magnetic properties compared to single-main-phase counterparts.
• The revealed magnetization reversal mechanisms provide insights for designing next-generation permanent magnets.