Microstructure characterization of high-energy product Nd-Fe-B thin film

A Si/Mo(50 nm)/Nd-Fe-B(400 nm)/Mo(50 nm) film with relatively high-energy product (BH)max⊥=247 kJ/m3) was prepared on a Si substrate heated at 650 °C. The microstructure of the film was investigated by X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HRTEM). The Nd-Fe-B thin film shows a notable out-of-plane c-axis texture. The (110) orientated Mo grains is proved to promote the growth of c-axis oriented texture of the Nd2Fe14B grains, which is favorable to achieve a high remanence. Nano-scale spherical Nd-O phases composed of randomly orientated polycrystalline grains and a sharp grain boundary without grain boundary phase between two Nd2Fe14B grains are observed. The coercivity highly depends on a certain amount of Nd-O phase and interface morphology.