Understanding the magnetic ground state of rare-earth intermetallic compound Ce4Sb3 : Magnetization and neutron diffraction studies

Magnetization and neutron diffraction studies have been performed on Ce4Sb3 compound (cubic Th3P4-type, space group I4_3d, no. 220). Magnetization of Ce4Sb3 reveals a ferromagnetic transition at 5 K, the temperature below which the zero-field-cooled and field-cooled magnetization bifurcate in low applied fields. However, a saturation magnetization (MS) value of only 0.93muB/Ce3+ is observed at 1.8 K, suggesting possible presence of crystal field effects and a paramagnetic/antiferromagnetic Ce3+ moment. Magnetocaloric effect in this compound has been computed using the magnetization vs. field data obtained in the vicinity of the magnetic transition, and a maximum magnetic entropy change, -DeltaSM, of 8.9 J/kg/K is obtained at 5 K for a field change of 5 T. Inverse magnetocaloric effect occurs at 2 K in 5 T indicating the presence of antiferromagnetic component. This has been further confirmed by the neutron diffraction study that evidences commensurate antiferromagnetic ordering at 2 K in zero magnetic field. A magnetic moment of 1.24muB/Ce3+ is obtained at 2 K and the magnetic moments are directed along Z-axis.