Crossover from ferromagnetic to antiferromagnetic ground state in the (Ce1-xUx)2Pd2.05Sn0.95 system

Abstract

The (Ce1-xUx)2Pd2.05Sn0.95 solid solution has been investigated by means of x-ray powder diffraction and magnetization measurements. All the compounds crystallize in the tetragonal U2Fe2Sn-type structure, P4/mbm space group. A crossover from ferromagnetic to antiferromagnetic behaviour at low temperature is observed around x0.30: in the composition range 0 x<0.30, the Curie tempertaure TC goes through a maximum at x0.10-0.15 whereas for 0.30 x<1.0 the Néel temperature TN increases continuously with x. Neutron powder diffraction performed on (Ce0.85U0.15)2Pd2.05Sn0.95 (x = 0.15) confirms the existence of a ferromagnetic structure below TC = 4.6(1) K, with (Ce, U) magnetic moments parallel to the tetragonal c-axis. The magnetic phase diagram ((TC, TN) against x) of this system is discussed considering a Ruderman-Kittel-Kasuya-Yosida model based on a non-spherical Fermi surface.