Successive Antiferromagnetic Transition in the Frustrated Compound CeMgIn

Abstract

We report on the magnetic, transport, and thermal properties of the hexagonal ZrNiAl-type compound CeMgIn with Ce atoms forming a distorted kagome network. This compound exhibits successive antiferromagnetic transition at $T_\text{N1} =$ 2.1 K, $T_\text{N2} =$ 1.7 K, and possibly $T_\text{N3} =$ 1.3 K. The electrical resistivity exhibits a minimum at 11 K and a nonlogarithmic increase with decreasing temperature down to $T_\text{N2}$. We found that CeMgIn is the first ZrNiAl-type compound whose resistivity increase can be well explained by considering a model in which the electron-spin scattering is enhanced by the magnetic frustration and the Ruderman-Kittel-Kasuya-Yosida interaction. These results suggest that CeMgIn is a notable compound whose physical properties are strongly affected by geometrical frustration. Since the Sommerfeld coefficient is 97 mJ/mol K$^2$, CeMgIn is classified as a moderate heavy-fermion compound.