Research On Preparation And Magnetic Properties Of Ndfeb/mo Multilayered Films

In this paper, the NdFeB target was fabricated by melting method, while the NdFeB single layers and NdFeB/Mo multilayered films were prepared by magnetron sputtering. The deposition rate, surface morphology, microstructure and magnetic property of films were investigated by means of SEM, AFM, XRD and VSM, respectively. Moreover, the influence of the multilayer structure and the crystallization treatment on the microstrure and magnetic property of NdFeB/Mo multilayer films was studied.The experimental results showed that the deposition rate, surface morphology and microstructure of the films were related to sputtering power and argon pressure. The increasing sputtering power was responsible for the increasing deposition rate, the grain size and the roughness. With increasing argon pressure, the deposition rate increased firstly and then decreased; magnetic property of the multilayer films changed with modulation cycle of NdFeB/Mo. When the modulation cycle was 10, the thickness of NdFeB layer was 216nm and the thickness of Mo layer was 7nm, multilayer film showed excellent magnetic property, namely, Hc⊥=1297Oe, Mr/Ms=0.37. The crystalline Nd2Fe14B phase can be derived from the amorphous as-fabricated NdFeB/Mo multilayer films by post annealing process. SEM and AFM observation indicated that the film was smooth and dense after crystallization treatment. With optimal crystallization treatment, the multilayer films showed high coercive force, remanence ratio and excellent perpendicular magetic anisotropy.The analysis showed that NdFeB single layers showed barely magnetic property because of the low magnetic property of smelting NdFeB target; while NdFeB/Mo nanocrystalline composite magnets were obtained by adding Mo layer of appropriate thickness, and its magnetic property can be enhanced effectively.