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arXiv · 1904.00064

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

Michael O. Ogunbunmi·Buyisiwe M. Sondezi·Harikrishnan S. Nair·André M. Strydom
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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, $γ$ 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, $μ_\mathrm{eff}$ = 3.37 $μ_B$/Pr and Weiss temperature, $θ_p$ = $-$124 K.

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Michael O. Ogunbunmi, Buyisiwe M. Sondezi, Harikrishnan S. Nair, André M. Strydom. 2019-03-29. Electronic and magnetic properties of quasi-skutterudite PrCo$_2$Ga$_8$ compound. https://doi.org/10.1016/j.physb.2017.10.091

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