Synthesis and Magnetic Properties of Magnetron Sputtered NdCoCr Thin Film on Fe₃O₄ Substrate

The NdCoCr film was deposited by magnetron co-sputtering on Fe₃O₄ substrate.The influence of the Co-content on the perpendicular magnetic anisotropy(PMA)and magnetic domain characteristics of Nd-Co films was investigated with X-ray diffraction,scanning electron microscopy and magnetic force microscopy(MFM).The preliminary results show that the Co-content had a major impact.Specifically,as the Co-content increased in amorphous NdCoCr film,the saturation magnetization(M_s)increased,and the effective magnetic anisotropy K_eff increased,especially at the initial growth stage.As shown in MFM images,the light and dark stripes appeared on the coating surfaces,being fairly pronounced at 0.6%(wt).Nd₄Co₃,Nd₂Co₁₇ and NdCoCr₂ phases formed in annealing at 600℃ for 30 m;and with the increase of Co-content,the coercivity of annealed a-NdCoCr first rapidly decreased and then slowly increased,minimizing at 0.4%,possibly because of the formation and precipitation of NdCoCr₅ and Nd₂Co₇ nano-grains.