The magnetic phases of pseudobinary Ce(Fe1-xMx)2intermetallic compounds; M=Al, Co, Ru

Powder neutron diffraction measurements of the magnetic and structural properties of a range of pseudobinary Ce(Fe 1-x M x ) 2 intermetallic compounds, with M=Al, Co, Ru, are reported. In each of these pseudobinaries addition of a small amount of the metallic impurity (M) to CeFe 2 reduces the ferromagnetic ordering temperature and enhances the small antiferromagnetic component which appears at low temperature. At higher impurity concentrations antiferromagnetism is achieved. This antiferromagnetism is accompanied by a cubic to rhombohedral distortion of the crystalline lattice. The antiferromagnetic component of the ordered moment in these compounds is oriented at approximately=18.5 degrees to the antiferromagnetic propagation vector ( tau =(111)). An ordered cerium moment is seen in the ferromagnetic phase of CeFe 2 and Ce(Fe 1-x Ru x ) 2 . This moment is coupled ferrimagnetically to the iron-sublattice moment and mu Ce / mu Fe approximately=-0.3.