Magnetic and Structural Characteristics of Lanthanide—Copper Compounds

Magnetic characteristics and structures of 11 intermetallic compounds represented by the formula LnCu are reported. The compounds with Ln = Ce, Pr, Nd, and Sm occur in the FeB structure; those with Ln = Y, Gd, Tb, Dy, Ho, Er, and Tm have the CsCl structure. YCu is a Pauli paramagnet. The magnetic characteristics of PrCu and NdCu are anomalous and attempts to deduce the nature of the cooperative magnetic phases in these materials, if any, at low temperatures are unsuccessful. Results for the other compounds suggest that they are antiferromagnetic at low temperatures. TbCu and HoCu exhibit two magnetic transitions; the high-temperature transition is interpreted as the Nèel point and the one at the lower temperature as an order—order transition in the antiferromagnetic state. In the paramagnetic region effective moments in good agreement with the free tripositive ion values are observed in all cases except for GdCu and ErCu. A variable moment is observed for ErCu whereas for GdCu a moment of 8.46 μB is obtained.