Magnetic properties of the heavy-fermion antiferromagnet CeMg3

Abstract

We have grown the single crystals of CeMg${}_{3}$ and its nonmagnetic analog LaMg${}_{3}$, which crystallize in the cubic crystal structure with the space group $\mathit{Fm}$$\overline{3}m$, and studied their magnetic properties on well-oriented single crystals by measuring the magnetic susceptibility, magnetization, electrical resistivity, and heat capacity. CeMg${}_{3}$ orders antiferromagnetically with a N\'eel temperature ${T}_{\mathrm{N}}$ of 2.6 K. The specific heat capacity at low temperature exhibits an enhanced Sommerfeld coefficient of 370 mJ/K${}^{2}$ mol, indicating the heavy-fermion nature of CeMg${}_{3}$. An estimation of the Kondo temperature ${T}_{\mathrm{K}}$ was made and it was found that it is of a magnitude similar to that of ${T}_{\mathrm{N}}$. The reduced value of the magnetization below the ordering temperature, together with the reduced entropy at the magnetic ordering temperature and the enhanced low-temperature heat capacity, indicates that Kondo effect plays a significant role in this compound. The electrical resistivity measurement suggests that CeMg${}_{3}$ is a Kondo lattice compound. We have performed a crystalline electric field (CEF) analysis on the magnetic susceptibility and the heat capacity data and found that the ground state is a ${\ensuremath{\Gamma}}_{7}$ doublet with an overall splitting of 191 K.