Unconventional ferrimagnetic ordering of Ce in the anisotropic metal CeCrSb₃

We report on the magnetization and electrical resistivity on single crystals of CeCrSb₃, a ferromagnetic metal with large anisotropy. It undergoes two ferromagnetic transitions: the first is at T_Cr=115 K due to the electrons from the Cr ions and the second is a gradual alignment of the Ce³⁺ 4f electrons between 48 and 18 K. The Cr moments behave similarly in LaCrSb₃, with the easy axis along the b axis. Below 48 K, the Ce moments begin to align along the c axis, and as the applied field increases, their effect on the magnetization increases in importance, resulting in nearly linear behavior of M_c(T) for H=30 kG. At 5 K, the saturation moment along the c axis is 3.28μ_B∕f.u., and along the b axis, the magnetization saturates to 1.29μ_B∕f.u., the difference being only 7% less than the predicted Hund’s rule value for Ce³⁺, indicating that the 4f moments have fully aligned along the c axis.