MAGNETIC-PROPERTIES OF GDXLA1-XCOSI

The magnetic properties and crystal structure of GdxLa1-xCoSi compound s (x=0, 0.25, 0.5, 0.65, 0.8, 1) are investigated. The anisotropy of t he magnetic properties are analyzed for a GdCoSi single crystal. The t emperature dependences of the magnetic susceptibility and the tetragon al lattice parameters of GdCoSi are characterized by anomalies in the vicinity of the magnetic phase transition temperatures, 166 K and 300 K. The Neel temperatures, the effective magnetic moments, and the para magnetic Curie temperatures of these compounds decrease as gadolinium is replaced by lanthanum. The compound LaCoSi is a Pauli paramagnet. T he results are discussed on the basis of a model that takes into accou nt the presence of positive and negative exchange interactions and the itinerant magnetism of the cobalt sublattice. (C) 1997 American Insti tute of Physics.