The two-dimensional metallic triangular lattice antiferromagnet CeCd3P3

Abstract

Single crystals of $R{\mathrm{Cd}}_{3}{\mathrm{P}}_{3}$ ($R=\mathrm{La}$ and Ce) have been investigated by magnetization, electrical resistivity, the Hall coefficient, and specific heat. Magnetization measurements of ${\mathrm{CeCd}}_{3}{\mathrm{P}}_{3}$ demonstrate clear quasi-two-dimensional magnetic behavior. Electrical resistivity and Hall coefficient measurements suggest that $R{\mathrm{Cd}}_{3}{\mathrm{P}}_{3}$ compounds are low-carrier-density metallic systems, in strong contrast to an earlier study of polycrystalline material. Specific heat and electrical resistivity measurements of ${\mathrm{CeCd}}_{3}{\mathrm{P}}_{3}$ reveal a high-temperature (structural) phase transition at ${T}_{s}=127$ K and antiferromagnetic ordering below ${T}_{N}=0.41$ K. Upon applying magnetic field in the easy-plane ($H\ensuremath{\parallel}ab$) the magnetic ordering temperature increases to 0.43 K at $H\ensuremath{\sim}15$ kOe, demonstrating partial lifting of the magnetic frustration. The large electronic specific heat persists in an unusually wide range of temperature above ${T}_{N}$ due to the frustrated spins. The observation of conventional metallic behavior in the electrical resistivity suggests that the $f$ electrons in ${\mathrm{CeCd}}_{3}{\mathrm{P}}_{3}$ undergo negligible hybridization with the conduction electrons. Thus, ${\mathrm{CeCd}}_{3}{\mathrm{P}}_{3}$ may be a model system for exploring the complex interplay between magnetic frustration and Ruderman-Kittel-Kasuya-Yosida physics on a low-carrier-density Ce triangular lattice.