Simultaneous Enhancement of Remanence and Coercivity in Anisotropic Nd–Fe–B Thick Films via Fe Composite and Tb Diffusion Layers

Modulations on the microstructure and magnetic properties of Nd-Fe-B thick films are essential for applications in microelectromechanical systems. In Nd-Fe-B/Fe multilayers, strong long-range dipolar interactions between hard and soft magnetic phases lead to the enhancement of remanence but result in lower coercivity. In this work, Tb diffusion layers are integrated into Nd-Fe-B/Ta/Fe multilayer thick films to systematically investigate the magnetic properties and coercivity mechanism. The results show that the introduction of Tb diffusion layers in Nd-Fe-B/Ta/Fe multilayers significantly enhances both remanence and coercivity, increasing the maximum energy product from 25.2 to 36.2 MGOe. Microstructural characterization and magnetization reversal analysis reveal that the multilayer structure improves crystallinity and promotes the <i>c</i>-axis texture of the main magnetic phase, while the long-range dipolar interaction between Fe and Nd-Fe-B layers effectively enhances the overall magnetization. Meanwhile, Tb diffusion strengthens domain wall pinning in the main magnetic phase, suppressing the inhomogeneous magnetization reversal induced by the Fe composite layers. Consequently, a simultaneous enhancement of the remanence and coercivity is achieved. This study provides insights into preparation strategies for high-performance Nd-Fe-B thick films.