Anisotropic magnetic behavior of single crystalline CeTiGe3 and CeVGe3.

ABSTRACT

We have grown the single crystals of iso-structural CeTiGe3 and CeVGe3 compounds by using Ce-Ge eutectic as flux. Using the techniques of magnetization, electrical resistivity and heat capacity, our data on single crystals reveal pronounced magnetic anisotropies in these compounds with hexagonal symmetry. The c-axis is the easy axis of magnetization in CeTiGe3 which orders ferromagnetically at 14 K, and a gap in the magnon excitation spectra of ∼ 28 K is inferred from both electrical resistivity and heat capacity. The electrical resistivity of CeTiGe3 shows anisotropic Kondo behavior and the heat capacity indicates the existence of the first excited crystal electric field split doublet lying at about ∼ 50 K. The nature of magnetic ordering changes to antiferromagnetic in CeVGe3, which undergoes a magnetic transition at TN ∼ 6 K with the a - b plane as the easy plane of magnetization. Below TN, the electrical resistivity of CeVGe3 along the c axis shows an upturn due to the opening of a gap. The 4f contribution to the resistivity ρ4f establishes that CeVGe3, like the Ti analog, is also a Kondo lattice compound. The present work on single crystals further advances our understanding of these materials based on polycrystalline samples which have been studied earlier in the literature.