Magnetic properties of Usub(1-x)Thsub(x)As and UAssub(1-x)Sesub(x) compounds

The thermal variation of the magnetic susceptibility of Usub(1-x)Thsub(x)As and UAssub(1-x)Sesub(x) compounds has been investigated by a mutual inductance technique. The magnetic phase diagram of these two compounds has been determined in zero field. Anomalies as peaks or jumps have been evidenced in the thermal variation of the magnetic susceptibility for both series of compounds, above the ordering temperature. Neutron diffraction experiments are necessary to know if these anomalies are associated with changes in the magnetic structures. For Usub(1-x)Thsub(x)As, as for UAssub(1-x)Sesub(x) compounds, additional conduction electrons are provided by thorium and selenium. The similarities between the magnetic behaviour of these compounds show that the conduction electrons play a fundamental role in their magnetic properties