On the magnetic and structural behaviour of the Nd50Fe40(Si1−xAlx)10 bulk amorphous alloys

Some amorphous materials with compositions Nd50Fe40Si10−xAlx (x=0–10 at.%) were studied with the view to enlarge the supercooled liquid region and to improve their hard magnetic properties at room temperature. We performed a comparative study for the alloys in ribbon and bulk shape. The partial or total replacement of Si with Al in the basic Nd50Fe40Si10 alloy leads to the increase of the glass-forming ability and allows to obtain thick amorphous ribbons having more than 100 μm in thickness by melt-spinning method and amorphous or partially vitrified bars with diameters up to 3 mm by mould casting. The large measured values at room temperature of the coercive force of the Nd50Fe40Si10−xAlx (x=0–10 at.%) amorphous samples as well as the observed anisotropies in magnetization and intrinsic coercive force can be explained by assuming the existence of the small ferromagnetic clusters in the amorphous phase.