Thermal and Transport Behavior of Single Crystalline R2CoGa8 (R = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) Compounds

TL;DR

This study investigates the electrical, magnetic, and thermal properties of single crystalline R2CoGa8 compounds, revealing charge density wave transitions, anisotropic magnetoresistance, and insights into crystalline electric field effects.

Contribution

It provides new experimental data on the anisotropic transport and thermal behavior of R2CoGa8 compounds, including evidence of charge density wave transitions and magnetic correlations.

Findings

Y2CoGa8 shows a possible charge density wave transition at ~30 K.

Gd2CoGa8 exhibits anisotropic magnetoresistance.

Dy2CoGa8 also shows signs of charge density wave transition.

Abstract

The anisotropy in electrical transport and thermal behavior of single crystalline R$_{2}$CoGa$_{8}$ series of compounds is presented. These compounds crystallize in a tetragonal structure with space gropup P4/mmm. The nonmagnetic counterparts of the series namely Y$_{2}$CoGa$_{8}$ and Lu$_{2}$CoGa$_{8}$show a behavior consistent with the low density of states at the fermi level. In Y$_{2}$CoGa$_{8}$, a possibility of charge density wave transition is observed at $\approx$ 30 K. Gd$_{2}$CoGa$_{8}$ and Er$_{2}$CoGa$_{8}$ show a presence of short range correlation above the magnetic ordering temperature of the compound. In case of Gd$_{2}$CoGa$_{8}$, the magnetoresistance exhibits a significant anisotropy for current parallel to {[}100{]} and {[}001{]} directions. Compounds with other magnetic rare earths (R = Tb, Dy, Ho and Tm) show the normal expected magnetic behavior whereas Dy$_{2}$CoGa$_{8}$ exhibits the possibility of charge density wave (CDW) transition at approximately same temperature as that of Y$_{2}$CoGa$_{8}$. The thermal property of these compounds is analysed on the basis of crystalline electric field (CEF) calculations.