MAGNETIC-PROPERTIES OF GDCO4-XMXB COMPOUNDS WHERE M = FE OR NI

The GdCo4-xNi(x)B alloys, for x less-than-or-equal-to 3 and GdCo4-xFe(x)B alloys for x less-than-or-equal-to 1.5 crystallize in a hexagonal structure of CeCo4B-type. The magnetic measurements performed in the temperature range 4.2-900 K show that GdCo4-xM(x)B compounds (M = Fe or Ni) are ferrimagnetically ordered. The mean cobalt moments increase when cobalt is substituted by iron and decrease when it is replaced by nickel. Above the Curie temperatures, the reciprocal susceptibilities for GdCo4-xNi(x)B alloys show a nonlinear temperature dependence. The exchange fields acting on cobalt atoms were evaluated. The variations of the cobalt moments are proportional to those of the exchange fields.