# Electronic and magnetic properties of quasi-skutterudite PrCo$_2$Ga$_8$ compound

## TL;DR

This study investigates the electronic and magnetic properties of the quasi-skutterudite PrCo₂Ga₈, revealing a low-temperature phase transition, enhanced quasiparticle mass, and tunable magnetic behavior linked to crystal electric field effects.

## Contribution

It provides the first detailed analysis of the phase transition, electronic correlations, and magnetic properties of PrCo₂Ga₈, highlighting its complex low-temperature behavior and potential for correlated electron phenomena.

## Key findings

- Phase transition at 1.28 K observed in resistivity and heat capacity.
- Enhanced quasiparticle effective mass indicated by high Sommerfeld coefficient.
- Magnetic susceptibility follows Curie-Weiss law with effective moment 3.37 μ_B/Pr.

## Abstract

PrCo$_2$Ga$_8$ is an orthorhombic quasi-skutterudite type compound which crystallizes in the CaCo$_2$Al$_8$ structure type, with space group $Pbam$ (No. 55). The Pr$^{3+}$ ion has a site symmetry of $C_s$ which predicts a crystal electric field (CEF) level splitting into 9 singlets for $J$ = 4. However, a phase transition at $T_m$ = 1.28~K is observed in electrical resistivity and specific heat results and is reported in this paper. The electrical resistivity shows an upturn below $T_m$ due to the superzone-gap formation. This transition is tuneable in fields and is suppressed to lower temperatures with applied magnetic fields. The electronic specific heat $C_{p}(T)/T$ increases below $T_m$ and reaches a value of 7.37 J/(mol K$^2$) at 0.4~K. The Sommerfeld coefficient, $\gamma$ extracted from the low temperature analysis of $C_\mathrm{4f}(T)/T$ is 637 mJ/(mol K$^2$) indicating a possible mass enhancement of the quasiparticles. The calculated entropy value of 3.05 J/(mol K) is recovered around $T_m$ exhibiting almost 53% of Rln2, where R is the universal gas constant. Magnetic susceptibility results obeys the Curie-Weiss law for data above 100 K with an estimated effective magnetic moment, $\mu_\mathrm{eff}$ = 3.37 $\mu_B$/Pr and Weiss temperature, $\theta_p$ = $-$124 K.