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arXiv · 0806.3573

Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K)

J. K. Dong·L. Ding·H. Wang·X. F. Wang·T. Wu·X. H. Chen·S. Y. Li
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Abstract

The specific heat $C(T)$ of BaFe$_2$As$_2$ single crystal, electron-doped Ba$_{0.7}$La$_{0.3}$Fe$_2$As$_2$ and hole-doped Ba$_{0.5}$K$_{0.5}$Fe$_2$As$_2$ polycrystals were measured. For undoped BaFe$_2$As$_2$ single crystal, a very sharp specific heat peak was observed at 136 K. This is attributed to the structural and antiferromagnetic transitions occurring at the same temperature. $C(T)$ of the electron-doped non-superconducting Ba$_{0.7}$La$_{0.3}$Fe$_2$As$_2$ also shows a small peak at 120 K, indicating a similar but weaker structural/antiferromagnetic transition. For the hole-doped superconducting Ba$_{0.5}$K$_{0.5}$Fe$_2$As$_2$, a clear peak of $C/T$ was observed at $T_c$ = 36 K, which is the highest peak seen at superconducting transition for iron-based high-$T_c$ superconductors so far. The electronic specific heat coefficient $γ$ and Debye temperature $Θ_D$ of these compounds were obtained from the low temperature data.

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J. K. Dong, L. Ding, H. Wang, X. F. Wang, T. Wu, X. H. Chen, S. Y. Li. 2008-06-30. Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K). https://doi.org/10.1088/1367-2630%2F10%2F12%2F123031

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