Excellent magnetic softness in TbFe/FeCoV multilayers

[Tb40Fe60(x nm)/Fe49Co49V2(y nm)](subscript N) multilayers were prepared by multitarget magnetron sputtering using a rotary turn-table technique in a stop-and-go mode. The multilayers were investigated using X-ray diffraction, field emission scan electron microscopy and vibrating sample magnetometry. The result shows that the coercive field drops abruptly with increasing number of bilayers, and it remains generally stable when the number of bilayers is 10 or higher. An excellent magnetic softness with a coercivity of 1.0 mT is obtained for x=5 and y=5 after annealing at 250℃. A crystalline state is observed in FeCoV layers before and after annealing by X-ray diffraction.