Tuning the crystalline electric field and magnetic anisotropy along the CeCuBi2-xSbx series

We have performed x-ray powder diffraction, magnetization, electrical resistivity, heat capacity, and inelastic neutron scattering (INS) to investigate the physical properties of the intermetallic series of compounds, CeCuBi2-xSbx. These compounds crystallize in a tetragonal structure with space group P4/nmm and present antiferromagnetic transition temperatures ranging from 3.6 to 16 K. Remarkably, the magnetization easy axis changes along the series, which is closely related to the variations of the tetragonal crystalline electric-field (CEF) parameters. This evolution was analyzed using a mean-field model, which included anisotropic nearest-neighbor interactions and the tetragonal CEF Hamiltonian. The CEF parameters were obtained by fitting the magnetic susceptibility data with the constraints given by the INS measurements. Finally, we discuss how this CEF evolution can affect the Kondo physics and the search for a superconducting state in this family.