Structure and magnetic properties of sputtered (Nd,Dy)(Fe,Co,Nb,B) \u3csub\u3e5.5\u3c/sub\u3e/M (M = FeCo,Co) multilayer magnets

The magnetic properties of nanocomposite multilayer magnets of the (Nd,Dy)(Fe,Co,Nb,B) 5.5/M (M = Co,FeCo) on Ti-buffered Si substrates have been investigated. X-ray diffraction results reveal that the Nd2Fe14B-type phase in almost all the films is randomly oriented. Different thickness x (nm) for Co layers and y (nm) for FeCo layers were adopted in the multilayers. It is found that high remanence is achieved in the nanocomposite multilayer films consisting of the Nd2Fe14B-type phase and soft magnetic phase for Co with 6≥x≥4 and for FeCo with 10≥y≥6. The enhancement of the remanence in the nanocomposite multilayer films is attributed to the exchange coupling between the magnetically soft and hard phases. Increasing the soft magnetic components results in a continuously decreasing coercivity