THE EFFECT OF SUBSTITUTION BY CERIUM ON THE STRUCTURE AND MAGNETIC-PROPERTIES OF THE COMPOUND NDFE2

The magnetic and magnetoelastic properties of Nd1-xCexFe2 have been in vestigated. The stable single Laves phase Nd1-xCexFe2 is synthesized a t ambient pressure for x greater than or equal to 0.2. The successful formation of this Lavas phase can be ascribed to the strong Ca 4f bond ing. Spin reorientation is observed around 150 K for Nd stoichiometric concentrations above 0.2. The lattice parameter, Curie temperature, l ow-temperature saturation magnetization and room-temperature anisotrop ic magnetostriction all increase with the Nd concentration. This indic ates that the effect of the Ce ion is only dilution of the magnetism. NdFe2 is ferromagnetic with an estimated magnetic moment of 5.36 mu(B) per formula unit. a Curie temperature of 589 K and a mom-temperature magnetostriction coefficient of 420 ppm. The largest saturation magnet ostriction 320 ppm, is obtained at x = 0.2. No apparent evidence of Ce ions changing their valence was observed.