Anisotropic magnetic properties of CeAg${}_2$Ge${}_2$ single crystal

Abstract

In order to investigate the anisotropic magnetic properties of CeAg${}_2$Ge${}_2$, we have successfully grown the single crystals, for the first time, by high temperature solution growth (flux) method. We have performed a detailed study of the grown single crystals by measuring their electrical resistivity, magnetic susceptibility, magnetization, specific heat and magnetoresistance. A clear anisotropy and an antiferromagnetic transition at $T_{\mathrm{N}}$ = 4.6 K have been observed in the magnetic properties. The magnetic entropy reaches $R$ ln 4 at 20 K indicating that the ground state and the first excited state are very closely spaced (a quasi-quartet state). From the specific heat measurements and crystalline electric field (CEF) analysis of the magnetic susceptibility, we have found the level splitting energies as 5 K and 130 K. The magnetization measurements reveal that the a-axis is the easy axis of magnetization and the saturation moment is ${\mu }_{\mathrm{s}}$ = 1.6 ${\mu }_{\mathrm{B}}$/Ce, corroborating the previous neutron diffraction measurements on a polycrystalline sample.

Submitted to Phys. Rev. B