Magnetic properties of cast $Nd60−xFe20Al10Co10Cux$ alloys

The effect of Cu on the magnetic properties of slowly cooled $Nd60−xFe20Al10Co10Cux$ $(0⩽x⩽10)$ bulk amorphous alloys has been studied by room-temperature magnetic measurements. Ferromagnetic bulk amorphous $Nd60Fe20Al10Co10$ cylinders of 3 mm diameter and 50 mm in length with a coercivity of 298 $kA m−1$ were obtained by copper mold casting. The addition of 1 at. % Cu into the $Nd60Fe20Al10Co10$ alloy causes an increase in coercivity to 321 $kA m−1.$ Further addition of Cu by replacing neodymium, however, results in an abrupt decrease in coercivity to 41 $kA m−1$ for alloys with $x=10$ due to the precipitation of a Fe-rich magnetically soft $Nd(Fe, Co, Al)2$ phase. The improvement of the hard magnetic properties by the addition of 1 at. % Cu for the cast $Nd60Fe20Al10Co10$ based bulk amorphous alloys may be attributed to an enhanced clustering of Nd–(Fe, Co) pairs in the amorphous alloys.