摘要
Rare earth permanent magnet nanostructures have attracted intensive interest recently due to the increasing demand for integrated and miniaturized devices.As a typical example,hard magnetic Nd_(2)Fe_(14)B-based nanostructures with desired coercivity have been developed by a reduction–diffusion process and the Nd-rich phase is supposed to be essential to optimize the magnetic properties,whereas the identification and role of the Nd-rich phase have not been addressed so far.Herein,Nd_(2)Fe_(14)B-based nanostructures with different Nd-rich phase contents,Nd_(15)Fe_(77)B_(8) and Nd_(14.2)Fe_(78.6)B_(7.2),are rationally prepared by a reduction–diffusion process.The coercivity of Nd_(15)Fe_(77)B_(8) can reach 5 kOe,which is higher than that of Nd_(14.2)Fe_(78.6)B_(7.2) of 3.2 kOe.First-order-reversal-curve (FORC) analysis confirms the amorphous paramagnetic Nd-rich phase as pinning centers and reveals magnetic interactions and magnetic domain nature in the two nanostructures.The increase of the Nd-rich phase optimizes microstructures and magnetic interactions,responsible for higher coercivity.This work points out the relationship between the Nd-rich phase,magnetic interactions,microstructures,and magnetic properties,and could usher in new ways of fabricating advanced permanent magnetic nanostructures.
基金
supported by the National Natural Science Foundation of China(51590882,51631001 and 51672010)
the National Key R&D Program of China(2017YFA0206301).
