Magnetic properties induced by chemical doping in RCuBi1.5Sb0.5(R=Pr, Nd) single crystals

In this work, we have investigated the structural and magnetic properties of the RCuBi1.5Sb0.5(R=Pr, Nd) compounds, grown by the Bi metallic flux method. X-ray diffraction patterns reveal that these compounds form in a tetragonal structure with the space group P4/nmmz. Measures of temperature and/or field dependent magnetic susceptibility, magnetization and specific heat show an interesting behavior for this family. Replacing Bi by Sb, it is observed a suppression of TN for PrCuBi1.5Sb0.5 compound while, the NdCuBi1.5Sb0.5 compound shows an emergence of TN. Additionally, we have found an easy and hard magnetic axis inversion for both synthesized Sb-doped compounds when compared to the parent compounds. Thus, we discuss the influence of Sb-chemical substitution on the crystalline electric field effects (CEF), which mainly govern the magnetic properties of these compounds [1-2]. The CEF properties were studied using a mean field model with tetragonal CEF Hamiltonian and magnetic exchanges parameters. From the best fits to our data, we have obtained the evolution of the scheme of the CEF levels and exchange parameters due to Sb-substitution for the studied compounds.