INVESTIGATION OF MAGNETIC-PROPERTIES OF NDMN2-XCOXGE2 COMPOUNDS (X = 0 TO 1.0)

The structure and the magnetic properties for the NdMn2-xCoxGe2 compou nds (x = 0 to 1.0) have been investigated. All the compounds crystalli ze in the ThCr2Si2-type structure. Substitution of Co for Mn led to a linear decrease in the lattice constants and the unit cell volume. Fro m the magnetic measurement we have determined two concentration region s of qualitatively different low temperature behavior. Increasing subs titution of Co for Mn in NdMn2Ge2 shows a depression of ferromagnetic ordering and a gradual development of antiferromagnetic ordering. For compounds with x < 0.6 ferromagnetic ordering occurs, while for compou nds with x greater than or equal to 0.6 antiferromagnetic ordering occ urs. The saturation magnetization at 1.5 K for these compounds decreas es monotonously with increasing Co content.