The tetragonal intermetallic compounds ${\mathrm{U}}_2$${\mathrm{Ni}}_2$In and ${\mathrm{U}}_2$${\mathrm{Rh}}_2$Sn have been studied by means of specific-heat, electrical-resistivity, and neutron-diffraction techniques. At low temperatures, both compounds order antiferromagnetically in a magnetic unit cell doubled along the c axis, and we find 5f moments of 0.60 and 0.38${\mathrm{\mu }}_{\mathit{B}}$/U atom for ${\mathrm{U}}_2$${\mathrm{Ni}}_2$In and ${\mathrm{U}}_2$${\mathrm{Rh}}_2$Sn, respectively. For ${\mathrm{U}}_2$${\mathrm{Ni}}_2$In, our refinement also indicates a possible Ni moment of 0.37${\mathrm{\mu }}_{\mathit{B}}$ perpendicular to the U moments. We discuss the development of the 5f moments together with findings on other isostructural ${\mathrm{U}}_2$${\mathit{T}}_2$X (T=transition metal, X=In, Sn) compounds, and confirm that the trends expected due to 5f-ligand hybridization also hold for this family of uranium compounds. Our analysis indicates different arrangements of the 5f moments in the two compounds (noncollinear arrangement within the basal plane for ${\mathrm{U}}_2$${\mathrm{Ni}}_2$In and collinear arrangement along the c axis for ${\mathrm{U}}_2$${\mathrm{Rh}}_2$Sn), although both compounds have nearest-neighbor U-U distances along the c axis. This would mean that the magnetocrystalline anisotropy in ${\mathrm{U}}_2$${\mathit{T}}_2$X compounds is not determined by nearest-neighbor U-U links alone. © 1996 The American Physical Society.

• Received 31 August 1995

DOI:https://doi.org/10.1103/PhysRevB.53.3263