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

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 $\gamma$ and Debye temperature ${\Theta }_D$ of these compounds were obtained from the low temperature data.

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Cited by in corpus (8)

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• Heat capacity study of BaFe${}_2$As${}_2$: effects of annealing
• Critical current and vortex dynamics in single crystals of Ca(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Magnetic order in orbital models of the iron pnictides
• Study of antiferromagnetic and nematic phase transitions in $BaF{e}_2(A{s}_{1-x}{P}_x{)}_2$ by AC micro-calorimetry and SQUID magnetometry